Automated digest summarizing changes to project for **external** collaborators dissemination

[anngvu]

More explicit, refined scope: this enhancement would be for researchers who are collaborating on the project.

Once tables are versioned (#1), it will be possible to summarize changes to the project, if this is decided as a useful-enough feature. For example, would the project members want a simple monthly or every-two-months summary of things such as (in order of presumably most important to least important):

1. Changes in rows of the clinical data tables (rows added, rows updated).
2. How many new files have been uploaded to each data folder?
3. Are there changes in data leads, expected dates, etc.?
4. Is there new content in the wiki or Sage Resources folder?