Support custom sources for packages

[ckdarby]

I wish while specifying the packages I want on the box that there was a tab that would allow custom sources for packages.

Recently I ran into this problem when I was trying to use Puphpet & my project required a custom source for the Redis package in order to get the latest version.

[HarasimowiczKamil]

👍
It will be great, to add this in Server Packages section to define sources for packages.

[lsmith77]

+1

[steefaan]

+1

[iamfinky]

+1 - given that elasticsearch won't install, the workarounds are getting frustrating. I'd be happy to sponsor this change request, if needed.