[BryceStevenWilley]

4 main changes:

• switches the dev setup to use supabase as a database instead of just standard postgres, so we can...
• use supabase's vault to store sendgrid API key secrets per server API key. Handles extracting the actual key automatically when it's going to send the email with sendgrid.
  • adding the custom api keys is a manual process; calling select vault.create_secret(...), and then UPDATE message_settings where server_id ... set sendgrid_api_key .... I don't want to make this an endpoint due to security concerns, and we'll likely be setting up the custom sendgrid keys ourselves, instead of making our partners do it.
• Keeps the same SENDGRID_API_KEY environment variable and uses it when the calling server doesn't have an API key setup (i.e. default behavior).
• Allows servers to use multiple from_emails, and can include that in the submission.

@nonprofittechy adding you as reviewer just so you can make sure this feature would work for how LITEFile wants to use it.

Fixes #375.

[BryceStevenWilley]

Confirmed that this works in SuffolkLITLab/LITEfile#349, so going to merge this.