[scraper]: Add support for deducing resource name from file path

[ulucinar]

Description of your changes

This PR adds support for deducing resource name from the markdown file's path if the scraper cannot extract it from the markdown file. It also adds the optional --resource-prefix command-line option to the scraper so that the calling repo can specify the prefix to be used as a prefix for the name extracted from the markdown file path. For example, for the hashicorp/google, this prefix is google because the markdown files are named with this prefix concatenated by the resource's name, e.g., google_network_management_connectivity_test.

I have:

• Read and followed Crossplane's contribution process.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

Tested via the upbound/provider-gcp here.
Also tested against the upbound/provider-{aws,azure}.

[sergenyalcin]

Thanks @ulucinar LGTM!