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.

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.

…sarif output

* Allow the codeql-action to be run locally

This change allows the codeql-action to be run locally through
[act](https://github.com/nektos/act).

In order to run the action locally, you need to do two things:

1. Add the `CODEQL_LOCAL_RUN: true` environment variable. The only way
   I could figure out how to do this was to add it directly in the
   workflow file in an `env` block. It _should_ be possible to add it
   through a `.env` file and pass it to `act`, but I couldn't get it
   working.
2. Run this command `act -j codeql -s GITHUB_TOKEN=<MY_PAT>`

Setting the `CODEQL_LOCAL_RUN` env var will fill in missing env vars
that the action needs, but isn't set by `act`. It will also avoid
making api calls to github that would fail locally.

This is a refactoring discussed in
https://github.com/github/dsp-codeql/issues/36