Remove jquery-ui and selectize dependencies

[kevinansfield]

We are currently bundling 2 large dependencies in the form of jquery-ui and selectize+ember-cli-selectize. jQuery UI is only used for drag-n-drop of the navigation items and re-ordering of tags. Selectize works well for our current use but is bloated due to needing to replicate a lot of functionality internally that Ember is much better at solving as well as needing a lot of sometimes flakey and inflexible glue code for communication and data munging between the jquery plugin and ember.

Our current and future use cases would be better served by switching to the much more lightweight and flexible ember-power-select + ember-sortable combo.

ember-power-select offers very composable and flexible suite of components that work directly with Ember data structures so it will make our future plans for extending the search bar a lot easier.

TODO:

• Switch navigation item drag-n-drop from jquery-ui.sortable to ember-sortable - Replace jquery-ui.sortable with ember-sortable for nav items #6468
• Switch gh-search-input from gh-selectize to ember-power-select - Convert gh-search-input to ember-power-select component #6492
• Switch tags input from gh-selectize to ember-power-select - Swap selectize tags input for ember-power-select+ember-drag-drop Admin#892
  • Modify autocomplete on tab, create on enter behaviour (see Have tags input autocomplete on Tab instead of Return #6912)
    • behaviour has changed slightly, both Tab and Enter will auto-complete the selected tag or create a new item if the Add "x"... option is selected
  • Style primary tags differently to normal tags (see screenshot below)
• Remove jquery-ui (+ additional plugins) and selectize dependencies - Swap selectize tags input for ember-power-select+ember-drag-drop Admin#892

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Update 10/10/2017: Finalisation of this has been blocked for a long time on ember-sortable not supporting x+y re-ordering. There is now an on-going spike at using ember-drag-drop instead in TryGhost/Admin#892.

Any solution that we end up on should allow for customisation of individual tags/tokens so that primary tags can be disambiguated: