feat(files): Use TS string parser for non-nightly versions

[kristijanhusak]

Summary

Since the removal of the string parser in #1041, some issues started to appear due to necessity to load the buffer for every org file that is defined in the configuration.
Since the issue with string parser is happening only on current Neovim nightly (v0.12-dev) version, we can use the string parser on all other stable versions.

Once Neovim nightly reintroduces string parser in different format (see #1049), we will switch only to that.

Related Issues

Related:

• Revert to string parser #1049
• Refactor deprecations and improve startup performance chipsenkbeil/org-roam.nvim#120

Closes #1048

Changes

• Introduce back the logic that uses the string parser
• If Neovim version is nightly, do not use the string parser (load buffer for each org file)
• If Neovim version is stable, use the old logic

Checklist

I confirm that I have:

• Followed the
  Conventional Commits
  specification (e.g., feat: add new feature, fix: correct bug,
  docs: update documentation).
• My PR title also follows the conventional commits specification.
• Updated relevant documentation, if necessary.
• Thoroughly tested my changes.
• Added tests (if applicable) and verified existing tests pass with
  make test.
• Checked for breaking changes and documented them, if any.

[kristijanhusak]

@seflue this should address your issue #1048 . Can you confirm this PR is working fine for you?

[seflue]

Hi @kristijanhusak, thanks for the PR, I appreciated the effort. I switched my local checkout of nvim-orgmode to your branch and have no obvious issue so far. I will try to use it productively the next days and will report back if I run into any problem.