remote: remote options validation

[ishikhman]

At the moment, there is no standard approach for options validations.
For example, --remote_http_cache=lololol will be considered by bazel as an option that enables remote cache, which would lead to some exception at some point of cache creation attempt.

The ideal situation would be:

• to identify fast that some option provided by user are malformed and notify the user about it asap in cases when bazel cannot recover/continue with invalid configurations
  • example: what should we do if --remote_cache is not a valid URI? Theoretically, we could execute build without caching, but should we? Because if the user specifies --remote_cache that they expect a build to be executed with that cache enabled.

[ishikhman]

Verify if #4595 is still an issue

[sgowroji]

Hi there! We're doing a clean up of old issues and will be closing this one. Please reopen if you’d like to discuss anything further. We’ll respond as soon as we have the bandwidth/resources to do so.