Bug 10104 - make koha-disable more robust

Bug 10104 - make koha-disable more robust

koha-disable now:

- checks for the existence of the instance before any actions on it.
- checks if the instance is already disabled before touching anything (warns otherwise)
- only reloads apache if needed
- handles more than one instance name.
- changed the docs to acknowledge the previous item.

To test:
- Apply the patch, build your package
- Run koha-disable on
  - Non existent instance (try names that are prefix and suffix of a valid one too please)
  - Already disabled instance name.
  - Enabled instance name.

It should work as expected and warn the user on the expected wrong cases.

Regards
To+

Sponsored-by: Universidad Nacional de Córdoba
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Mason James <mtj@kohaaloha.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>