Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Related to https://etke.cc/news/d3uw4utq4t3_rpxicrrfqqou_ynmptqjgk95pt-3n2s/

It only serves a metrics endpoint, so it shouldn't try to capture
anything else.

We no longer ask users to create Matrix user accounts for these bots:

- Postmoogle
- Honoroit
- Reminder Bot

Other bots and services (matrix-registration-bot, maubot, mjolnir,
Dimension, etc.) require an Access Token to run (not a password),
so this new role doesn't help for them.

It does help for the above bots though, and for defining your own
"initial user accounts" in the `matrix_user_creator_users_additional`
variable.