Add enable setting for ability to do project-specific disabling

[savetheclocktower]

I sometimes make contributions to projects which have very opinionated, noisy, or outdated ESLint configs. Sometimes they have silly ESLint plugins that I don't want to install. Sometimes I'm running pulsar-ide-typescript-alpha and the linting I'm getting from typescript-language-server is more than enough.

These are all scenarios in which I'd want a quick way to disable linting on an entire project (even when it's set up for ESLint) without disabling the package altogether. With an explicit Enable option, I can easily configure a project-specific override with project-config/atomic-management or by adding "enable": false to a .linter-eslint file.

[scagood]

Nice changes, one little comment

[savetheclocktower]

The test failures are all on the CI-only tests; looks like something about the environment setup isn't quite right, and the job isn't giving us useful error messages. I'll see if I can track down the root cause, but in the meantime I'm fine with landing this if you are.