Text-processing for changes

[nicho90]

The ability to see what was changed from the previous to the current revision could increase the efficiency during the review process. For example: After a document was already reviewed and accepted by a member of the Ethics committee, the researcher edited something (maybe just one word or a simple typo), s/he has to submit the document again. Now, the reviewer has to read through the whole document again to see what was changed. A text-processing tool, which highlights the changes (red for deletions/modifications, green for editions) would be very helpful. On GitHub or other collaborations tools, such a function is often called "text differencing" or "diff". I found some possible implementations here:

• https://github.com/google/diff-match-patch.git
• https://github.com/kpdecker/jsdiff

[nicho90]

@SpeckiJ Mostly done. Please checkout the feature/diff branch.

[nicho90]

@SpeckiJ Done ✅