Create a `EmojiMentionIntegration` plugin

[pomek]

📝 Provide a description of the new feature

The goal is to allow for inserting emoji after typing :.

In other words, let's use the Mention plugin as a base.

We can initially use the emoji-picker-element-data package as input data. We may change it at some point.

Definition of Done

• The name is temporary, and it's subject to change.
  • Confirm the name with @Witoso.
• After typing a colon, we should display a dropdown that allows for inserting emoji.
  • I would require a single character before reviewing the database.
• We need a manual test that allows the feature to be tested.
• We need automated tests for the new code.
• Feature branch and a pull request should target the #epic/ck/17361 branch.

[Witoso]

My thoughts:

• this plugin is a part of Emoji plugin, I don't see the reason to split it to two separate plugins. Internally it can be split of course.
• If there's Mention config with : this plugin should not be enabled and warn to the console about the conflict.
• Have some sensible max, GH has 5, GDoc 15? We 10?