Packages all, none and lib should be reserved and rejected from Hackage

[ezyang]

They conflict with the suggested cabal new-build all command in #3391, and also with -allow-newer and -allow-older (which will parse all as "apply allow newer to all packages" rather than just one).

If we aren't going to reserve these, then there needs to be a way of disambiguating these cases.

[ezyang]

CC @hvr, @23Skidoo, @dcoutts , @phadej

[23Skidoo]

Should be as easy as adding a new check to D.PD.Check (if we go the first route).

[hvr]

I've made sure ppl can't upload "all" or "none" to hackage; I'm considering implementing a trustee-maintainable blacklist regexp or similiar in hackage-server, as there's a few magic names we don't want packages to squat

[23Skidoo]

A early-warning check is probably still a good idea.

[phadej]

someone could have all and none packages locally. If we want to use them as keywords, they should be invalid PackageName, i.e. fail (or warn?), already in the parser.

[ezyang]

Added lib to the list, see #3763