WIP: Public Meetings API

@DSASanFrancisco/portal-members

A follow up for !306 (merged) - this PR will actually open up the meetings API.

A few things to do in this regard:

• remove auth requirement for API
• remove auth requirement for front end

Future considerations

• friendly meeting links (e.g. https://members.siliconvalleydsa.org/attend/april-branch-meeting, which we can shorten using a regex-capable redirector to https://sv-dsa.org/attend/april-branch-meeting).
• adding a checkbox to meetings like Zoom for generating a random value as a "password" for each meeting. When visiting the meeting link, the server will check the query parameter for unauthenticated members. This can help prevent arbitrary meetings sign ins by discovery-attacking our meeting ID.

I have:

• Included a summary of the changes
• Linked all relevant Trello tickets to this request
• Linked all relevant GitLab issues to this request (optional -- prefer Trello, but GitLab is easier for fast-follow cleanup issues)
• Listed all dependent merge requests in this summary (optional)

added 1 commit

• 388e44d5 - Blacken

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added 55 commits

• 388e44d5...101b644d - 53 commits from branch DSASanFrancisco:dev
• dcaf8afd - Add `optional_auth` decorator to provide an AuthContext if available
• 0f50f6c9 - Blacken

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added 33 commits

• 0f50f6c9...bcbd7763 - 32 commits from branch DSASanFrancisco:dev
• 056627ee - Add `optional_auth` decorator to provide an AuthContext if available

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added 2 commits

• d496a466 - Blacken
• d96759be - Better typings for get_auth0_token

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