Add detection for GitHub AE.

Allow overriding path of temporary files.

Lock bundler version to 2.2.9.

This commit adds two new ways of specifying GitHub auth:

1. from the GITHUB_TOKEN environment variable
2. from standard input

This commit does not include any documentation changes and the
descriptions of new command line options will need to be tweaked.

Specifying a token as a cli input leads to a potential for leaking the
token on CI logs. This commit removes the option. Instead, users
should specify a single GitHub token through `--github-auth-stdin` or
by setting the `GITHUB_TOKEN` environment variable. This token should be
created with enough privileges to access the required repository.

Mitigation for OOM errors (137/SIGKILL) seen by users when we overcommit the available memory.
For Unix, reserve 1GB.
For Windows, reserve 1.5GB, as the OS needs more memory and estimates inaccurately.

Remove --external-repository-token option from runner

Also look for the CodeQL bundle at the custom GitHub AE endpoint.

Set externalRepoAuth

Increase the default amount of RAM reserved for the OS