Rather than via properties on default exports — see
https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-named-as-default-member.md

This is a functionality that never worked perfectly and hasn't been
used for a while.

This allows developers to run the action on their local machine, but
the run was always flaky and never 100% mirrored what was happening on
the actions runner.

This PR ensures environment variables are set before any invocation of
the CLI.  Here is a list of vars that are set:

https://github.com/github/codeql-coreql-team/issues/1124#issuecomment-852463521

This ensures the CLI knows the features and versions of the containing
actions/runner.

Additionally:

- Fix the user agent so that it more closely aligns with user agent
  spec
- Refactor environment variable initialization so that it all happens in
  one place and call.
- Move Mode, getRequiredEnvParam, setMode, getMode out of actions-util
  and into util. actions-util is meant for utils only called by the
  action, not the runner.

The `prepareLocalRunEnvironment()` method is most likely deprecated and
should be removed. I originally added it because I had a way of working
where I would run the action from my local machine to test out changes,
but this was always a little flaky. So, I no longer use this way of
working. I will probably remove it soon.

spelling: executable
spelling: github
spelling: javascript
spelling: latest
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Signed-off-by: Josh Soref <jsoref@users.noreply.github.com>

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.

testing-utils.ts / setupTests() already stores and restores the env

Resolves #206

…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