RFC: Cache the code of conduct text

[TimJentzsch]

Currently, we pull the CoC text every time a new user starts transcribing:

tor/tor/core/user_interaction.py

Line 198 in 51d4eeb

coc_not_accepted.format(get_wiki_page("codeofconduct", cfg)),

Instead, the text should be cached and only pulled whenever the bot gets restarted or the !reload command is executed.

Advantages

• More efficient
• Less interactions with the Reddit API

Disadvantages

• We have to remember executing !reload when we change the CoC. We would need to add this to the wiki.