✨ fix push notifications features and reorganize UI

[JGreenlee]

closes e-mission/e-mission-docs#1130

-have the Dockerfile copy over the conf/ directory. for triggering push notifs to work, we need to provide push provider credentials (which we have JSON files for). we will place them in conf/ on the internal repo (nrelopenpath-admin-dashboard), while the public repo will just have the sample file

-reorganized the UI to make it clearer what these features do and used dash-bootstrap-components instead of basic HTML. -unified the "UUIDs" and "Emails" selection into one "Users" dropdown, which lists them by UUID and/or opcode depending on what permissions are granted
-added ability to filter users by subgroups

-got rid of the "Survey Spec" options and replaced with more generic "Push Actions". also fixed the format of the payload (it was sending a string where a dict is expected)
-current actions are "Visible Notification" and "Trigger Config Update". The config update is not handled on the phone yet
-left some bits of the "Survey" feature as comments. We don't support it now, but later we may implement a feature for admins to send a one-time survey via push notification

[JGreenlee]

Testing done:

• Added push.json and the firebase credentials JSON to conf/
• docker compose -f docker-compose-dev.yml build
• docker compose -f docker-compose-dev.yml up -d
• Selected an opcode I'm using on a test phone and sent notification with title "test" and message "test message"
• Received notification on test phone

I also tried this with minimum config version set to 1 – the phone does not handle this, but the notification still shows up (i.e. it did not fail)