Bootstrap 5 & remove jQuery (#661)

* build: move frontend assets to Bootstrap 5.3 and Tom Select

* feat: migrate templates and scripts to Bootstrap 5, dropping jQuery

Templates
- Rename Bootstrap 4 classes and data attributes (data-bs-*, ms-/me-/ps-/pe-,
  text-start/end, form-group -> mb-3, input-group wrappers removed, badges,
  custom controls -> form-check/form-select, media -> d-flex, btn-close, ...)
- Dark mode now uses Bootstrap 5.3 colour modes (data-bs-theme on <html>),
  set from <head> to avoid a flash of the light theme
- Remove the Bootstrap 4 /bootstrap/ demo page
- Contextual table classes (table-success etc.) still work as plain
  backgrounds for the rigboard key

JavaScript
- Remove jQuery: src.js/interaction.js and every inline template script are
  rewritten in plain JS on top of small helpers (helpers.js, bundled with
  Bootstrap into jpop.js so inline scripts can use them)
- Replace bootstrap-select/ajax-bootstrap-select with Tom Select. The remote
  search now sends the `q` parameter and reads `text`, which is what the
  API actually uses (the old picker sent `term` and read `label`)
- HTML fragments are fetched with an X-Requested-With header so views keep
  rendering their modal variants, and fetched scripts are re-executed
- Remove the Bootstrap 4 plugin script includes

* fix: stop rigboard header buttons stretching to full width under Bootstrap 5

* fix: restore dark-mode brand colours and contextual table colours under Bootstrap 5

* fix: brighten dark-mode links and make coloured card outlines visible

* fix: calendar layout and grid borders, navbar search button width, guard missing modal links

* fix: readable text in dark-mode Tom Select inputs and placeholders, restore form-control column widths

* build: split the Dockerfile into cached stages with prod and dev targets

* deploy: make compose.yml development-only with live reload, and document it

* fix: keep badge text colour for links inside badges

* fix: restore table-bordered grid lines in dark mode

* fix: include Bootstrap's progress styles and keep progress labels readable

training/templates/level_detail.html

@@ -16,28 +16,15 @@
 {% endblock %}
 
 {% block js %}
-    <script src="{% static 'js/autocompleter.js' %}"></script>
-    <script src="{% static 'js/tooltip.js' %}"></script>
     <script>
-    $('document').ready(function(){
-        $('#requirement_button').click(function (e) {
-             e.preventDefault();
-             var url = $(this).attr("href");
-             $.ajax({
-                url: url,
-                success: function(){
-                    $link = $(this);
-                    // Anti modal inception
-                    if ($link.parents('#modal').length === 0) {
-                        modaltarget = $link.data('target');
-                        modalobject = "";
-                        $('#modal').load(url, function (e) {
-                            $('#modal').modal();
-                            $(".selectpicker").selectpicker().each(function(){initPicker($(this))});
-                        });
-                    }
-                }
-             });
+    ready(function(){
+        var link = document.getElementById('requirement_button');
+        if (!link) { return; }
+        link.addEventListener('click', function (e) {
+            e.preventDefault();
+            modaltarget = undefined;
+            modalobject = "";
+            loadModal(this.getAttribute("href"));
         });
     });
     </script>
@@ -45,7 +32,7 @@
 
 {% block content %}
 {% if request.user.is_supervisor %}
-<div class="col-sm-12 text-right pr-0">
+<div class="col-sm-12 text-end pe-0">
 <a type="button" class="btn btn-success mb-3" href="{% url 'add_requirement' pk=object.pk %}" id="requirement_button">
 	<span class="fas fa-plus"></span> Add New Requirement
 </a>
@@ -58,7 +45,7 @@
     </div>
 </div>
 <div class="card">
-    <div class="card-header"><h4 class="card-title">Level Requirements</h4> {% if u.pk != request.user.pk %}<h5 class="card-subtitle font-italic">for {{ u }}</h5>{% endif %}</div>
+    <div class="card-header"><h4 class="card-title">Level Requirements</h4> {% if u.pk != request.user.pk %}<h5 class="card-subtitle fst-italic">for {{ u }}</h5>{% endif %}</div>
     <div class="table-responsive card-body">
         <table class="table">
           <thead>
@@ -70,7 +57,7 @@
           </thead>
           <tbody class="table-body">
             {% for level in object.prerequisite_levels.all %}
-            <tr data-toggle="collapse" data-target="#{{level.pk}}" style="cursor: pointer;"><th colspan="3" class="text-center font-italic" data-toggle="collapse" data-target="#level_{{level.pk}}">{{level}} (prerequisite)</th></tr>
+            <tr data-bs-toggle="collapse" data-bs-target="#{{level.pk}}" style="cursor: pointer;"><th colspan="3" class="text-center fst-italic" data-bs-toggle="collapse" data-bs-target="#level_{{level.pk}}">{{level}} (prerequisite)</th></tr>
             <tr id="level_{{level.pk}}" class="collapse">
               <td><ul class="list-unstyled">{% for req in level.started_requirements %}<li>{{ req.item }} {% user_has_qualification u req.item 0 %}</li>{% endfor %}</ul></td>
               <td><ul class="list-unstyled">{% for req in level.complete_requirements %}<li>{{ req.item }} {% user_has_qualification u req.item 1 %}</li>{% endfor %}</ul></td>
@@ -135,7 +122,7 @@
     </div>
 </div>
 <div class="row">
-    <div class="col text-right">
+    <div class="col text-end">
     {% include 'partials/last_edited.html' with target="traininglevel_history" %}
     </div>
 </div>