Add comment WRT values for the Group field

[Olf0]

Never saw a reference, so document it now.

[nephros]

The Group tag is mandatory if the spectacle tool is used via a .yaml file, as spectacle wants it to be filled with a value from that list.

As we don't use spectacle (and Group is optional from an RPM point of view) we might as well remove that Tag completely. (Qt/Qt isn't a very valuable entry anyway.)

[Olf0]

The Group tag is mandatory if the spectacle tool is used via a .yaml file, as spectacle wants it to be filled with a value from that list.

Ack.

As we don't use spectacle (and Group is optional from an RPM point of view) we might as well remove that Tag completely. (Qt/Qt isn't a very valuable entry anyway.)

O.K. I simply intended to document where valid values can be found, so one can pick an more appropriate Group tag later.

I have no idea if anything else but Spectacle evaluates the Group tag; if you are sure that nothing else does, I am fine with removing it.

P.S.: The Group: Qt/Qt statement seems to be something which was copied to almost all SFOS applications.

[Olf0]

Looking at the list, I think that both Applications/System and System/System Control (but nothing else) suits Patchmanager well. I picked the latter, because it is less generic (as Qt/Qt was criticised as too generic, which is absolutely justified).

P.S.: @nephros, please note that I deliberately used "should", not "must" or "shall", because without utilising Spectacle and the Jolla Store, we are free to use or define any group; still I think it makes sense to adhere to the ones defined by Jolla, which is not hard, because the list offers lots of well defined choices.