advoptions-list: Add additional dhcp options - fixes bug 12291

advoptions-list: Add additional dhcp options - fixes bug 12291

- Add ms-classless-static-routes and rfc3442-classless-static-routes as options for dhcp
   These are apparently required for deployiong classless IP routes
- Original static-routes option is not intended for classless IP routing but is being
   left in place for backward compatibility
- The option "rfc3442-classless-static-routes" is for normal clients
- The option "ms-classless-static-routes" is for Microsoft clients

Fixes: bug 12291
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Michael Tremer <michael.tremer@ipfire.org>
Reviewed-by: Peter Müller <peter.mueller@ipfire.org>