Update default mirror and build-mirror

According to https://wiki.debian.org/DebianGeoMirror, httpredir.debian.org is discontinued, and deb.debian.org should be used.

Update the default options in freedom-maker to point to the current mirror URL.

Created by: coderark

working on it.

Created by: SunilMohanAdapa

I have merged the patch.

Created by: SunilMohanAdapa

I have built a new image with the patch applied and checked that build process and actions later are doing well.