{Graph} Refactor role module for Microsoft Graph migration

[jiasli]

Code refactoring

• Replace azure.graphrbac SDK interactions with model-less dict operations
• Sort functions in src/azure-cli/azure/cli/command_modules/role/custom.py into logical groups for easier developer collaboration and source control
• Extract src/azure-cli/azure/cli/command_modules/role/msgrpah (similar to https://github.com/microsoftgraph/msgraph-sdk-python-core) to officially introduce msgraph.GraphClient so that it can be re-used by other modules or extensions
• Introduce msgraph.GraphError for model-less error handling
• Rename msgraph.GraphClient methods: for non-create POST API like addPassword, use ...add_password, instead of changing it to ...password_add

Test refactoring

• Migrate test replacers for Microsoft Graph: MSGraphClientPasswordReplacer, MSGraphUserReplacer
• Manually test all az ad/role commands to be working
• Re-organize test cases into reasonable logical groups like ApplicationScenarioTest
• Rewrite all tests to adapt to Microsoft Graph, especially dropping AD Graph permission tests for az app permission
• Re-run all tests for az ad/role so that the recording contains Microsoft Graph requests

This PR paves the way for complete Microsoft Graph migration (#22174).

[yonzhan]

Graph