Implement renvs

It started with packrat in #53 (closed)# and after some testing I decided that it was worth it to add it as a function to our workflow. Still under testing.

added mass_spec rna_seq labels

added 45m of time spent at 2019-09-16

See commits bf3b29e3 and f13cb600.

added 45m of time spent at 2019-09-13

After quite some testing and exploration, I don't think this is worthwhile pursuing for now due to a number of complications:

1. renvs is designed for a specific project structure which we don't use. There is solution to overcome this, but it requires one too many hacks. Basically it is not elegant and it might be hard to maintain.
2. the envinronment needs to be maintained locally and in the cluster because the packages are compiled with different libraries. So any change to a project in the cluster needs to be propagated (manually) locally.

All of these issues are solvable and renvs are still a valid option for some projects, but I am not completely convinced it will solve our reproducibility issues.

closed