Feature Request: Support multi-guild signups

[ssilve1989]

Is your feature request related to a problem? Please describe.
A lot of the commands deal with a singular collection in the database, but these collections should be scoped by guild.
Everything the bot does should be scoped by guild to make the development process easier.

Describe the solution you'd like
A clear and concise description of what you want to happen.
The structure should be something like /guilds/{guildId}/settings /guilds/{guildId}/signups etc.
Some commands almost got this structure right, but it should be standardized.

[jjjakey]

I just got a development env set up and working just now so I plan to work on this sometime this week. A lot of this is outside my typical experience so I'll likely be very slow while I sift through documentation for the various frameworks along with learning TS.

It looks like the job collection is already structured the way we want it, so I'll use that as a reference for the standardization.

/settings/{guildId}                →  /guilds/{guildId}/settings
/encounters/{doc}                  →  /guilds/{guildId}/encounters
/signups/{doc}                     →  /guilds/{guildId}/signups
/blacklist/{guildId}/documents     →  /guilds/{guildId}/blacklist
/guilds/{guildId}/jobs             →  /guilds/{guildId}/jobs