Shortcuts for conversations

[Choucroute-melba]

What is it?

• [ ] Bugfix
• [x] Feature
• [ ] Codebase improvement

Description of the changes in your PR

• Added ShortcutHelper class
• Publishong shortcuts for each used thread

This changes add conversation shortcuts to the launcher. They also aim to integrate the app in the Android conversation space.

Fixes the following issue(s)

• Fixes #209

Acknowledgement

• [X] I read the contribution guidelines.