Update the line about `expulsion from the community`

[jenlampton]

If a community member engages in unacceptable behavior, the community organizers may take any action they deem appropriate, up to and including a temporary ban or permanent expulsion from the community without warning (and without refund in the case of a paid event).

I have concerns about "permanent expulsion" from "the community" for "unacceptable behavior" without more careful consideration. The change below would make it specific to an event:

If a community member engages in unacceptable behavior at an event, the event organizers may take any action they deem appropriate, up to and including a temporary ban or permanent expulsion from the event without warning (and without refund in the case of a paid event).

I'm okay with this section being limited to an event context, so let's start there and iterate.

Changes needed:

• make something similar that applies to both online and in-person contexts
• consequences in one context (online) may have results in another (in-person)
• specifically state that someone may be removed from any leadership positions (such as the PMC) and have privileges revoked (such as commit access on github).