Update the tag form in the question details with tom-select

[akatsoulas]

No description provided.

[akatsoulas]

PR mozilla/kitsune#6381

[emilghittasv]

The tag form was successfully updated to tom-select.

All elements are functional (addition or deletion of tags on both desktop & mobile devices).

During the verification of this ticket I've noticed that the tags no longer act as a community forum search filter (filled and tracked in #2085)

Moving this ticket inside the release column.