feat: add `options` table

[vhyrro]

rocks-config.nvim is a general Neovim configuration suite including plugins.

This small code snippet allows a [config.options] to be provided to set neovim options.

An interesting complement for this feature would be https://github.com/nvim-neorocks/rocks.nvim/issues/240

[github-actions[bot]]

Review Checklist

Does this PR follow the Contribution Guidelines? Following is a partial checklist:

Proper conventional commit scoping:

• For example, fix(installer): some installer bugfix

• [ ] Pull request title has the appropriate conventional commit prefix.

If applicable:

• [ ] Tested
  • [ ] Tests have been added.
  • [ ] Tested manually (steps in PR description).
• [ ] Updated documentation.

[mrcjkb]

Might be a good idea to add an entry to the readme