Add new framework for dataconect e2e test

[joehan]

Description

Setting up a framework to test more complicated schema migration and deployment cases. I've started with just a few simple cases, but we can add more in the future.

The main changes here:

• Every case is run on a separate, fresh DB and service, so no false no-op positives
• Cases are now 'sequences' of schemas/connectors to deploy, to let use test migration from different starting states

[joehan]

😢 Chasing down access to the target project so that we can enable the data connect API and run tests on it

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 10.46512% with 77 lines in your changes missing coverage. Please review.

Please upload report for BASE (jh-client-improvements@362df1d). Learn more about missing BASE report.

Files	Patch %	Lines
src/emulator/dataconnectEmulator.ts	8.69%	63 Missing :warning:
src/emulator/portUtils.ts	14.28%	6 Missing :warning:
src/emulator/downloadableEmulators.ts	0.00%	2 Missing :warning:
src/gcp/cloudsql/cloudsqladmin.ts	33.33%	2 Missing :warning:
src/dataconnect/client.ts	50.00%	0 Missing and 1 partial :warning:
src/emulator/hub.ts	0.00%	1 Missing :warning:
src/emulator/registry.ts	0.00%	1 Missing :warning:
src/rc.ts	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## jh-client-improvements #7309 +/- ## ========================================================= Coverage ? 53.83% ========================================================= Files ? 387 Lines ? 26263 Branches ? 5400 ========================================================= Hits ? 14138 Misses ? 10860 Partials ? 1265 ```

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