* pkgs: refactor needless quoting of homepage meta attribute
A lot of packages are needlessly quoting the homepage meta attribute
(about 1400, 22%), this commit refactors all of those instances.
* pkgs: Fixing some links that were wrongfully unquoted in the previous
commit
* Fixed some instances
This fixes builds after #4419. Thanks to @vbgl for the original commit;
I changed that as I'm not sure whether passing null values to buildInputs is clean.
CC maintainers: @coroa, @peti, @phreedom, @robberer, @jcumming.