Feature request: `!rss notice * false`

[axiopaladin]

It would be nice to allow setting the !rss notice variable to false as a bot-wide (or room-wide) default. I prefer it to use the m.text for all messages, but it's a hassle to do that for each and every feed individually.

Possible UI:

• In a room: !rss notice * false to set all feeds in the room to m.text
• In the bot config: default_notice: true, which can be changed to false to set all feeds in all rooms to m.text by default.