switch underlying matrix library from gomatrix to mautrix-go

[metskem]

Since the gomatrix library is no longer supported, I think we should switch to mautrix-go.

[sebhoss]

Thanks a lot!

AFAIK the room joining part was added so that the initial setup in a complete new rooms works fine, e.g. in our case we have to invite the bot account to a room and the bot has to somehow accept that invitation before being able to send messages. Does this work in the new library without doing an explicit join?

[metskem]

Ah, I missed that. And no, I don't think mautrix-go will allow uninvited members to send messages either. So that would have to be added back in again.
In our test cases we explicitly invited the bot account and also logged in with the bot account to accept the invite.
If you have time please add it, or I can do it somewhere during the weekend or Monday.

[sebhoss]

Ok ok - let see who is faster 😄

edit: Or maybe a better approach would be to document who bot accounts can be created and added to rooms? Since that action is only necessary once I always thought that this room joining code was kinda annoying

[sebhoss]

@metskem thanks a lot!