docs: more details about git workflow

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
docs: more details about after-merge updates

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
homepage: FIX testimonials

* corrects file path for json
news: removes links on authors
templates: animated physics objects GIFs

* Adds animated GIFs showing good and bad objects.
  (closes #228) (PR #288)
templates: "Other CMS open data" above "Policies"

* Fixes error introduced in previous change. Policies are now at bottom
  of page.  (PR #277)