Migrate admin site to tabler

[mickzijdel]

This is coding in the open atm. Closes #35.

Progress Tracker

• Sidebar
• Header
• Home Page with widgets
• Generic index page -> See if it can be more compact
• Generic forms
• Breadcrumbs
• Pagination -> It is a bit low contrast. I really like the adminlte one so might just need to lift that
• Login Page
• Stars Rating
• Collapses
• Validation
• Footer
• Error page template
• Tabs on MD editor
• Tables
• Autosize
• Potentially litepicker for dates
• Potentially icons (we keep hitting the limit for fontawesome)
• Dropzone
• Gallery (attachments, pictures, video links)
• Replace select2 with tomselect, which is integrated, or something ele. Otherwise, change the theme.
• Update picture and attachment fields to display in a 3-per-row grid again #263 -> Check out gallery documentation
• Get rid of the bottom margin in rendered markdown. #262
• Attachments Gallery Thumbnail Fitting #249
• Put quick actions underneath the description instead of the search form in the admin index #184
• Collapsing the search form on mobile devices #182
• Make the /admin/ site redder #162
• Merge quick actions with the search form actions? Doesn't really work when there's an editable block.
• I do not really like the collapsible search form currently. Maybe the whole search form should collapse instead? Maybe the link to open should just be way smaller rather than using the default collapsible section. Ask people for their thoughts.

Afterwards

• Move to import maps -> Use a CDN instead of locally hosting bootstrap, fontawesome, and other dependencies #257
• Move from ujs to turbo -> Support for Ajax page transitions (like Rails' Turbo) tabler/tabler#1828
• Get rid of cocoon -> Replace cocoon #314
• Get rid of remaining jquery (select2 and sprinkled in scripts)