use reflector about archinstall_gui

[Torxed]

Adding in the reflector in the mirrors step would be a good idea.
Could be used in junction with filtering regions.

[Torxed]

Some tweaks have been done in the mirror process.
Among other things, the https://www.archlinux.org/mirrors/status/json/ is now being used to load an active mirror-list.

We then filter active and https mirrors in order to avoid dead mirrors and "unsafe" mirrors, even tho signature per package is done, it's some how scary to trust HTTP.

Future work will include custom mirrors not listed in the official mirror-list: #11

Edit: should also mention we use rankmirrors to optimize even a filtered list of mirrors.