Secure https plugins

[whilefoo]

Resolves #43

[0x4007]

Glad to see that you are pushing code again.

[gentlementlegen]

@whilefoo Thank you for this. Will you take care of implementing it in the relevant plugins as well?

[whilefoo]

Yes I have implemented it in command-query-user because I needed to test it, but I'm not sure which plugins we plan to switch to workers. All plugins are short-running so I guess we can switch all?

[gentlementlegen]

I believe that https://github.com/ubiquibot/comment-incentives and https://github.com/ubiquibot/user-activity-watcher would remain as Actions because they might be long running tasks. Otherwise since all the others are handling commands yes I believe they can all be Workers (and I think it's already the case).

Side note, plugins can even be hybrids with both Worker and Action if that is ever necessary someday.