[Key Vault] Add KeyVaultSettingsClient

[mccoyp]

Description

Resolves https://github.com/Azure/azure-sdk-for-python/issues/26869. Based on https://github.com/Azure/azure-sdk-for-js/pull/23643, https://github.com/Azure/azure-sdk-for-java/pull/31705, and https://github.com/Azure/azure-sdk-for-net/pull/31984.

The changes to generated code are from regenerating with API version 7.4-preview.1 specified as the explicit default; newer versions of autorest now only use the latest stable API version as the default version otherwise.

Tests are expected to fail until recordings are updated.

All SDK Contribution checklist:

• [x] The pull request does not introduce [breaking changes]
• [x] CHANGELOG is updated for new features, bug fixes or other significant changes.
• [x] I have read the contribution guidelines.

General Guidelines and Best Practices

• [x] Title of the pull request is clear and informative.
• [x] There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• [ ] Pull request includes test coverage for the included changes.

[azure-sdk]

API change check

APIView has identified API level changes in this PR and created following API reviews.

azure-keyvault-administration

[mccoyp]

/azp run python - keyvault - ci

[azure-pipelines[bot]]

Azure Pipelines successfully started running 1 pipeline(s).

[mccoyp]

Everything is good to go for KV -- the analyze failure is coming from a different package's dependency that doesn't match a frozen requirement. Overriding CI for now

[mccoyp]

/check-enforcer override