Add schema and glob resolution validation actions.

[0xv1n]

Adds some scripts to automate:

1. Make sure new entries adhere to YAML schema, and won't break the site build
2. Uses platform images to verify and validate glob patterns actually resolve to what they should using the binary basenames (or full cmdlet). Theres some caveats, like aliases and non-wildcard globs (cough %COMSPEC%) which will always skip validation, as these are just windows env vars that point to a KV-pair, not a glob expansion.