Sync eng/common directory with azure-sdk-tools for PR 8929 (#37240)

* Refactor prepare-pipelines

* Convert pipeling generation single to use template

* Convert to pwsh for setting the variables

* Fix switch expression

* Add path separator in front of devopspath

* Continue on error for individual step failures

* Remove unnecessary parameters

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Co-authored-by: Wes Haggard <[email protected]>
Co-authored-by: Wes Haggard <[email protected]>

Author: azure-sdk