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

templates/generic_form.html

@@ -17,7 +17,7 @@
 {% block js %}
     {{ block.super }}
     <script>
-    $(document).ready(function () {
+    ready(function () {
         setupMDE('.md-enabled');
     });
     </script>
@@ -29,21 +29,21 @@
         <div class="row">
             <div class="col-md-6">
                 {% include 'form_errors.html' %}
-                <div class="form-group form-row">
+                <div class="mb-3 row g-2">
                     <label for="{{ form.name.id_for_label }}"
                            class="col-sm-2 control-label">{{ form.name.label }}</label>
                     <div class="col-sm-10">
                         {% render_field form.name class+="form-control" placeholder=form.name.label %}
                     </div>
                 </div>
-                <div class="form-group form-row">
+                <div class="mb-3 row g-2">
                     <label for="{{ form.phone.id_for_label }}"
                            class="col-sm-2 control-label">{{ form.phone.label }}</label>
                     <div class="col-sm-10">
                         {% render_field form.phone class+="form-control" type="tel" placeholder=form.phone.label %}
                     </div>
                 </div>
-                <div class="form-group form-row">
+                <div class="mb-3 row g-2">
                     <label for="{{ form.email.id_for_label }}"
                            class="col-sm-2 control-label">{{ form.email.label }}</label>
                     <div class="col-sm-10">
@@ -51,7 +51,7 @@
                     </div>
                 </div>
 
-                <div class="form-group form-row">
+                <div class="mb-3 row g-2">
                     <label for="{{ form.address.id_for_label }}"
                            class="col-sm-2 control-label">{{ form.address.label }}</label>
                     <div class="col-sm-10">
@@ -60,7 +60,7 @@
                 </div>
             </div>
             <div class="col-sm-6">
-                <div class="form-group form-row">
+                <div class="mb-3 row g-2">
                     <label for="{{ form.notes.id_for_label }}"
                            class="col-sm-2 control-label">{{ form.notes.label }}</label>
                     <div class="col-sm-10">
@@ -68,7 +68,7 @@
                     </div>
                 </div>
                 {% if form.three_phase_available is not None %}
-                <div class="form-group form-row">
+                <div class="mb-3 row g-2">
                     <div class="col-sm-10 col-sm-offset-2">
                         <div class="checkbox">
                             <label>
@@ -79,7 +79,7 @@
                 </div>
                 {% endif %}
                 {% if form.union_account is not None %}
-                <div class="form-group form-row">
+                <div class="mb-3 row g-2">
                     <div class="col-sm-10 col-sm-offset-2">
                         <div class="checkbox">
                             <label>
@@ -91,7 +91,7 @@
                 {% endif %}
             </div>
         </div>
-        <div class="form-group text-right">
+        <div class="mb-3 text-end">
             {% button 'submit' %}
         </div>
     </form>