Add options to install and enable missing packages from apt

[sunjam]

#1125, option to add smbclient from the ncp menus.
#1177 add option to add php-imageck and bmath from the ncp menus.

This feature request is for installing packages / dependencies missing within the default NextcloudPi installations. The current method is for the admin to install these via apt-get, but that is not persistent in Docker method. I understand these are not included by default, but it would make sense to make them a one click fix, which is also in-line with the way Docker images are designed.

Thanks for considering!

[sunjam]

If considered, method that would make the most sense for non-interactive is:

$ apt-get update
$ apt-get -y install --no-install-recommends $PACKAGE
$ apt-get clean

This avoid installing unnecessary additions outside the required packages in apt-get.

[segator]

The problem to do it by hand is that if you reinstall the docker everything is lost.. something that in case we use kubernetes to deploy applications is a very common case :(
we need a way to inject an script in runtime to install packages.

[C-Fu]

I think this would be awesome and probably needed for CUPS and the Printer App #1288

[nachoparker]

I think that the best way of achieving this is to build a new docker image with the NCP image as a base, and install any extra stuff you might want