feat(record/amend): add support for detecting and adding untracked files

[claytonrcarter]

This updates git record and git amend to automaticaly detect (and optionally add) new, untracked files.

There are 4 modes of operation, configurable via command line option and config setting:

• disable (default): do nothing; don't look for untracked files on disk/in db
• skip: new files are not added, will remain skipped in subsequent invocaions
• add: new files are added to the commit
• prompt: user will be prompted for what to do with each new file

Notes:

• As noted above, this behavior it totally disabled by default. It must be enabled either via CLI option, or via the config setting.
• Untracked files are considered "new" if they are detected on disk, but aren't in the cached list from last run (ie in the db).
  • Every invocation of record/amend updates a cache of "known" untracked files, stored in our internal sqlite db.
  • Because the cache is updated on every invocation, a previously skipped file may be treated as a new file if was deleted and later recreated.
• Config setting branchless.record.untrackedFiles is provided to change the default runtime behavior, ie when --untracked is not used
• If there are staged changes, then no untracked files are added/prompted.
• A list of "known" (previously skipped) files is printed at runtime. Admittedly, this can be sort of annoying, but it is intended to help maintain "situational awareness" and reduce confusion about why the feature is behaving in a particular way. This may need to be reconsidered based on user feedback.
• When new files are skipped, a hint is shown to remind the user that
  • they will remain skipped forever
  • if they need to be added, they need to do so manually, via git add