[Task]: Reconfigure Github Actions CI/CD for mono-repo structure

[daphnegold]

Summary

Blocked by #139
#299 #300 should be completed prior to this ticket (see below)

Note: Infrastructure + Github Actions should exist before this ticket can be worked on. This can be done in multiple ways, at the discretion of whoever picks up this issue:

1. Incrementally, in coordination and piecemeal as front-end or back-end infrastructure are set up
2. First either front-end or back-end is set up, then this is done in tandem with the remaining
3. As a fast follow up task after back-end and front-end infra, where CI/CD will not function as intended until this is completed

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Template applications are meant to be in separate repositories. Some work needs to be done for the Github Actions to run appropriately in a mono-repo after template infra is implemented for both frontend and API. See links for more context.

navapbc/template-infra#238
https://nava.slack.com/archives/C03G1SWD9H7/p1689363837120939

Acceptance criteria

• Modify Github Actions workflows
• Test (I haven't tried this, but there are ways to run GA locally now, please report back how it goes!)

[SammySteiner]

Adding here so we don't forget, update inputs from type of string to choice wherever possible to reduce the chances of typos breaking things or things failing to run.