[Breadth Coverage] Onboard Custom Providers Commands

[jsntcy]

What does this PR do?

• Support the key use case for Custom Providers.
• Issue link is [Breadth Coverage] Onboard CustomProviders Commands azure-cli#12452

Which commands will be supported?
az custom-providers resource-provider create
az custom-providers resource-provider update
az custom-providers resource-provider show
az custom-providers resource-provider delete
az custom-providers resource-provider list

---

This checklist is used to make sure that common guidelines for a pull request are followed.

General Guidelines

• Have you run azdev style <YOUR_EXT> locally? (pip install azdev required)
• Have you run python scripts/ci/test_index.py -q locally?

For new extensions:

• My extension description/summary conforms to the Extension Summary Guidelines.

[azuresdkci]

If this PR is for a new extension or change to an existing extension, use the following to try out the changes in this PR:

docker run -it microsoft/azure-cli:latest
export EXT=<NAME>
pip install --upgrade --target ~/.azure/cliextensions/$EXT "git+https://github.com/jsntcy/azure-cli-extensions.git@bc-customproviders#subdirectory=src/$EXT&egg=$EXT"

[yonzhan]

add to S169

[mmyyrroonn]

LGTM in general. Cheers

[mmyyrroonn]

example