Refactor autocomplete/emoji input

Problem:

Wrapping input/textarea in an another component makes it harder to access the said component from outside - you have to use $ref and such, punching through a component. Also currently autocomplete uses a flimsy custom thing and should use proper Popper.

Solution should be something like a mixin that enhances an existing input/textarea.

Possible solutions:

1. Custom vue directive
2. Component that takes input/textarea as a slot.