Update public documentation links to include the PyPI package in the url

[parthea]

It would be helpful if we include the PyPI package name in the url for the public documentation to make it easier to quickly navigate to the documentation for a specific package.

For example, for google-cloud-backupdr, the documentation exists here instead of here.
https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-backupdr

IOW, we should have google-cloud-backupdr in the url

https://cloud.google.com/python/docs/reference/google-cloud-backupdr/latest/summary_overview

instead of

https://cloud.google.com/python/docs/reference/backupdr/latest/summary_overview

Similarly, for google-cloud-quotas, it should be

https://cloud.google.com/python/docs/reference/google-cloud-quotas/latest/summary_overview

instead of

https://cloud.google.com/python/docs/reference/google-cloud-cloudquotas/latest/summary_overview

As part of this bug, we should audit all packages, and make sure it is easy to navigate to the docs by url with only the package name.

[parthea]

As part of the solution, we should ensure that both the old and the new urls work so that there are no broken links.
eg.
Both https://cloud.google.com/python/docs/reference/google-cloud-quotas/latest/summary_overview and https://cloud.google.com/python/docs/reference/google-cloud-cloudquotas/latest/summary_overview work