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

RIGS/templates/hs/power_form.html

@@ -17,8 +17,6 @@
 
 {% block js %}
     {{ block.super }}
-    <script src="{% static 'js/autocompleter.js' %}"></script>
-    <script src="{% static 'js/tooltip.js' %}"></script>
 {% endblock %}
 
 {% block content %}
@@ -48,19 +46,19 @@
                                 <dd class="col-8">{% include 'partials/event_size.html' with object=event.riskassessment %}</dd>
                             </dl>
                             <hr>
-                            <div class="form-group form-row" id="{{ form.power_mic.id_for_label }}-group">
+                            <div class="mb-3 row g-2" id="{{ form.power_mic.id_for_label }}-group">
                             <label for="{{ form.power_mic.id_for_label }}"
                                 class="col-4 col-form-label">{{ form.power_mic.help_text }}</label>
-                                <select id="{{ form.power_mic.id_for_label }}" name="{{ form.power_mic.name }}" class="selectpicker col-8" data-live-search="true" data-sourceurl="{% url 'api_secure' model='profile' %}?fields=first_name,last_name,initials" required="true">
+                                <select id="{{ form.power_mic.id_for_label }}" name="{{ form.power_mic.name }}" class="ts-select col-8" data-live-search="true" data-sourceurl="{% url 'api_secure' model='profile' %}?fields=first_name,last_name,initials" required="true">
                                     {% if power_mic %}
                                         <option value="{{power_mic.pk}}" selected="selected">{{ power_mic.name }}</option>
                                     {% endif %}
                                 </select>
                             </div>
-                            <div class="form-group form-row" id="{{ form.venue.id_for_label }}-group">
+                            <div class="mb-3 row g-2" id="{{ form.venue.id_for_label }}-group">
                                 <label for="{{ form.venue.id_for_label }}"
                                 class="col-4 col-form-label">{{ form.venue.label }}</label>
-                                <select id="{{ form.venue.id_for_label }}" name="{{ form.venue.name }}" class="selectpicker col-8" data-live-search="true" data-sourceurl="{% url 'api_secure' model='venue' %}">
+                                <select id="{{ form.venue.id_for_label }}" name="{{ form.venue.name }}" class="ts-select col-8" data-live-search="true" data-sourceurl="{% url 'api_secure' model='venue' %}">
                                 {% if venue %}
                                     <option value="{{venue.pk}}" selected="selected">{{ venue.name }}</option>
                                 {% endif %}
@@ -190,7 +188,7 @@
             </div>
             {% endif %}
             <div class="row mt-3">
-                <div class="col-sm-12 text-right">
+                <div class="col-sm-12 text-end">
                     {% button 'submit' %}
                 </div>
             </div>