Don't ban moderators or those in the control room

[Mikaela]

Draupnir has inherited the confusing punishing moderators issue from Mjolnir and Matrix is somewhat hostile towards moderators trying to release other moderators from it.

• Protections can ban mods for ban/redact events matrix-org/mjolnir#200
• Mjolnir shouldn't ban moderators even if it has higher power / exempt moderators from protections / don't punish admin room users matrix-org/mjolnir#341 (@Raatty)

[Gnuxie]

This is most easily implemented as a filter on the final policy revision issuer that filters out any policies targetting room moderators.

To make this work, it'd have to log all the policies that match a moderator as it filters them out, since they could be an important glob rule.

This means it probably wants to be considered with allow/disallow. the-draupnir-project/planning#3 #193

[Gnuxie]

Another way is to just nerf all the capabilities by giving them a special membership revision with the moderators. But idk i don't like that because it's still soft, what i mean by that is that if someone cooks up a new capability they can forget about this functionality and cause problems. There are much less capabilities than there are protections and call sites so we might get away with it, and capabilities are supposed to be trusted.

Either way Element have made a move on this feature in Mjolnir matrix-org/mjolnir#544.

I don't really feel too great about the only barrier to being able to use the bot is being a member of the room, I feel like there should be a safety check on top of that, like a power level in the management room or something. Not to consider in this issue though