remove additional_repo and add pkg and add modules

[MalloZup]

info:

We should remove un-used variables for keep codebase minimal.

This 3 variables at least 2 (add repo and add pkgs) aren't really needed for our use-cases.

The add-modules perhaps

[MalloZup]

assigning people for sharing thoughs!

[MalloZup]

an historic thing: if we need to introduce devel_mode variable this mean that this 2 variable are also more useless then neeeded.

I think in a way encouraging to install pkg is not needed. If people want to add Additional pkgs, they can do later after install/ We should own the control of input and remove vars as possible.

[arbulu89]

I wouldn't remove features that are already tested and working.
In my opinion they don't add much maintenance work and are quite easy to manage.
Removing things is quite tricky as we don't know if anyone is using them. I know that this project is still small and doesn't have users except us, but we always need to think about the impact of these changes.
PD:
The reg_additional_modules is in fact used to add PackageHub packages.

[MalloZup]

we have removed some of the vars. right now I think this is issue got staled and we can remove vars in future if needed