Remove unused CFN_RESOURCE_PROVIDER_OVERRIDES option

[dominikschubert]

Motivation

While this technically removes an option, it was one that has not been communicated and was only used internally for configuring generated tests. Even that hasn't been relevant since we've switched to prioritizing newer resource providers over the legacy ones by default.

Changes

• Remove config CFN_RESOURCE_PROVIDER_OVERRIDES and all usage

[github-actions]

S3 Image Test Results (AMD64 / ARM64)

  2 files    2 suites   3m 28s ⏱️
392 tests 341 ✅  51 💤 0 ❌
784 runs  682 ✅ 102 💤 0 ❌

Results for commit 60cfab5.

[coveralls]

coverage: 85.889% (+0.004%) from 85.885%
when pulling 60cfab5 on cfn-cleanup
into cc55cb4 on master.

[github-actions]

LocalStack Community integration with Pro

    2 files      2 suites   1h 28m 44s ⏱️
2 691 tests 2 435 ✅ 256 💤 0 ❌
2 693 runs  2 435 ✅ 258 💤 0 ❌

Results for commit 60cfab5.

[thrau]

LGTM! if it wasn't documented as part of the public config API, no need to really treat it as a major change 👍