User documentation for `colony_mask_features` scripts

[pgarrison]

Currently the README.md file does not mention any of the scripts in the colony_mask_features folder. If we want users to discover and use those, we need to write instructions in the top-level README.

There is a README at EMT_data_analysis/colony_mask_features/README.md that the top-level README can reference. In addition, I expect users would benefit from context on how the colony_mask_features scripts fit in the context of this repo & the paper.

[mfs4rd]

added to current PR

[pgarrison]

added to current PR

@mfs4rd I'm not seeing this in #30? If it isn't there, I think it would be more appropriate to add it in a new PR

[mfs4rd]

@pgarrison After reviewing the code I'm thinking that we should remove this from the repo. This code was for processing new data on our resources and I don't think it's of use to anyone trying to reproduce our results for the paper