Refactor configuration options

Is your feature request related to a problem? Please describe.
Options aren't 'in the same direction' at the moment. Would be nice to remove disable_ strings from them and switch bools around.

{
  disable_signs = false,
  disable_hint = false,
  disable_context_highlighting = false,
  disable_commit_confirmation = false,
  auto_refresh = true,
  disable_builtin_notifications = false,
}

This is subset of current options. Please note how auto_refresh is 'positive' while all others are 'negative' (disable_).

Describe the solution you'd like
It would probably make sense to group related options into subtable and turn them around, so instead of disable_signs = false default would be signs = true, but also would be nested into, let's say, display subtable (display.signs = true).

Describe alternatives you've considered
Leave things as they are but setup table will eventually become polluted.

Additional context
https://github.com/TimUntersberger/neogit/pull/225#discussion_r724809237

Start by reviewing the configuration options listed in the issue and the linked pull-request discussion. Determine the intended grouping and naming scheme before locating all current option definitions and uses. Done means the configuration is consistently organized without breaking existing setup behavior.