Linter rule to suggest against targetScope = tenant

It seems there's not really any practical reason to use `targetScope='tenant'`, as tenant-scoped resources can be deployed from Bicep files at other scopes. Also, `targetScope = 'tenant'` requires tenant-level permissions, which very few users have.

This seems like a good candidate for a linter rule, maybe to point customers to a doc explaining this and why they should avoid it?

Start by locating the linter-rule entry points and documentation associated with the Bicep targetScope declaration. Confirm how tenant-scoped resources can be deployed from other scopes and define the expected warning and documentation link for targetScope='tenant'. Done means the rule and its guidance clearly discourage unnecessary tenant-scope usage.

Written by the indexing model from the issue text.