change ambiguous activityId / campaignId / roomId

[ArEyeses79]

The club activity request urls were previously using a notation where {activity type}Id was used to mean the activityId for an activity of that type, except for campaigns where campaignId did indeed mean the campaign's campaignId and not its activityId.
This was confusing since rooms used roomId to mean the room's activityId and not its roomId.

This pr changes the notation to use activityId whenever an activity ID is required, only leaving campaignId whenever a campaign ID is required.

[davidbmaier]

Looks alright, just a small nitpick.

[davidbmaier]

Thanks 👍