Have a way to mark Bazel releases as bad and ignore them

This of course shouldn't apply when the Bazel release is requested explicitly.

The need for this came up in the discussion of https://github.com/bazelbuild/bazel/issues/13502. Fortunately, Philipp came up with a fix quickly but having this feature would have given us more time if we would have needed it.

Start by tracing how Bazelisk selects Bazel releases and handles explicitly requested versions. Read the discussion in bazelbuild/bazel#13502 for the motivation, then define how a bad release would be recorded, ignored during normal selection, and still honored when explicitly requested.

Written by the indexing model from the issue text.