* Reflect the debian manifest we want
* Update json schema to reflect new base-url entries
* Have a util in place to retrieve apt mirrors
* Have repo url in repos hash
* Cover various usages of apt-repos
* Initial add of option to use internal APT repo for builds
* Pet flake8
* Wrap a long f-string
* Use f-string in right place
* Fix usage of single / double quotes
* Move to apt_get_base_url as a function
* Undo dyslexia
* Log which base url we are using in bootstrap for debugging
* Add missing location to use the base url in bootstrap
* Use base url when bootstrapping the ISO as well
* Add APT_BASE_CUSTOM as another override option if the builder
wants to pull from some location other than the two in our manifest
This commit fixes an issue where we were not adding our custom apt mirrors before installing some basic packages like build-essential etc. Problem was that these packages pull in packages like openssl which we want to pull from specific apt mirror based on our apt preferences rather then using whatever is being provided with the default apt mirrors from debootstrap.