Feature: Tags Support

[abhishek97]

This issue is related to: coding-blocks/trouble-maker#19
and the bounty is for the combined task and is listed there.

We need UI to tag questions. So for every question, we need a multiple-select searchable dropdown to add tags to a question.

There should be some UI to create tags as well.

[haquezameer]

@abhishek97 taking this up.