Make miniconda installation more userfriendly

[pirmink]

To install miniconda, the user is referred to tmpl/tools/setup_miniconda.sh. It is nice that this script is provided, but when running it, miniconda is installed in the current working directory. Now a separate miniconda installation for every package is probably not what the average user wants, it should rather be installed in a common place for all packages. The option to do that can however only be found by inspecting the script, as it is neither documented in the README.md nor does the script have a -h or --help option. There is also no indication how to activate conda after installation (with conda init). And it seems that the README in the template, that will become the top README of each package based on the blueprint, doesn't even mention conda/miniconda as prerequisite at all.

[clairemerker]

Thanks for the feedback. I think this script is mainly provided to be able to install miniconda in the jenkins tests. This is the reason conda init is not called as the default, since it caused troubles to have the conda block inserted in jenkins' bashrc.
I don't know if we want to change the defaults... But we should document a bit better! Could you maybe prepare a PR @pirmink if you are figuring it out for your installation anyways? Thanks!

[clairemerker]

Closed by #126