Support alpha and azure pipeline build version formats for SemVer parsing and sorting

[benbp]

This PR updates the semver tooling to support our dev feed formats like:

5.3.0-alpha.20200928.3
# Python
2.0.0a20201208001

Supporting this format will enable us to sort release feeds that contain alpha releases, primarily so we can target smoke tests against the latest nightly and/or preview release, where applicable. Currently the smoke tests (at least for .net) have a bug where they are testing against very old dev releases, since they just pick the last item in the API response.

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[benbp]

@weshaggard support added for optional zero-padding in non-python build versions. Updated the sorting and toString to handle [string]BuildNumber.

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[weshaggard]

A couple questions but otherwise looks good.

[azure-sdk]

The following pipelines have been queued for testing:
java - template
java - template - tests
js - template
net - template
net - template - tests
python - template
python - template - tests
You can sign off on the approval gate to test the release stage of each pipeline.
See eng/common workflow

[ghost]

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