Update apollo service in docker compose to wait for graphql service

[joshmeek]

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Please describe your work and make sure your PR:

• adds new tests (if appropriate)
• add a changelog entry in the changes/ directory (if appropriate)
• updates docstrings for any new functions or function arguments, including docs/outline.toml for API reference docs (if appropriate)

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What does this PR change?

This PR makes use of server's post-start.sh to have the apollo service properly wait for the graphql service to be running and healthy.

This PR depends on PrefectHQ/server#41

Why is this PR important?

In its current form we will commonly see an error when running prefect server start that looks like:

apollo_1    |
apollo_1    | > @ serve /apollo
apollo_1    | > node dist/index.js
apollo_1    |
apollo_1    | Building schema...
apollo_1    | { FetchError: request to http://graphql:4201/graphql/ failed, reason: connect ECONNREFUSED 172.31.0.4:4201
apollo_1    |     at ClientRequest.<anonymous> (/apollo/node_modules/node-fetch/lib/index.js:1455:11)
apollo_1    |     at ClientRequest.emit (events.js:182:13)
apollo_1    |     at Socket.socketErrorListener (_http_client.js:392:9)
apollo_1    |     at Socket.emit (events.js:182:13)
apollo_1    |     at emitErrorNT (internal/streams/destroy.js:82:8)
apollo_1    |     at emitErrorAndCloseNT (internal/streams/destroy.js:50:3)
apollo_1    |     at process._tickCallback (internal/process/next_tick.js:63:19)
apollo_1    |   message:
apollo_1    |    'request to http://graphql:4201/graphql/ failed, reason: connect ECONNREFUSED 172.31.0.4:4201',
apollo_1    |   type: 'system',
apollo_1    |   errno: 'ECONNREFUSED',
apollo_1    |   code: 'ECONNREFUSED' }
apollo_1    | Trying again in 3 seconds...

This is due to docker-compose telling apollo it can start because the graphql container is up however the graphql service has not finished standing itself up—thus leading to this error. This error output can be confusing to new users.

[codecov]

Codecov Report

Merging #3150 into master will not change coverage.
The diff coverage is n/a.

[cicdw]

This LGTM but let's hold off on merging until we can rebuild the server images and chat about server / core image compatibilities. Ultimately @jlowin and I landed on this proposal: #3149 but I want to have something like that in place prior to releasing this enhancement.

[cicdw]

This is so much cleaner now! Nicely done