Add a "usual_reporters" field in the project configuration so the bot reacts with the project emoji

[thibaultamartin]

It would be useful for deployments of Hebbot with many known projects to have the possibility to add a usual_reporters to individual projects, as follows:

[[projects]]
emoji = '📻'
name = 'shortwave'
title = 'Shortwave'
description = 'Internet radio player with over 25000 stations.'
website = 'https://gitlab.gnome.org/World/Shortwave'
default_section = 'circle'
usual_reporters = [
    '@felix:homeserver.net',
    '@thib:serverhome.org'
]

In the example above, if either Felix or Thib report news to Hebbot, it will react with the 📻 emoji. The editors then only need to click the emoji to sort it in the Shortwave project.

If a same reporter is listed in several projects' usual_reporters list, the bot reacts with the emojis of each projects the reporter is listed in, and the reporter can then click on the one actually related to the report.