Web page template update: "last updated"

[joeflack4]

Description

Update pages / entries so that date last updated is shown.

Additional notes

Just quoting something from note taking from Yeonsoo (@ybaik10) from focus group discussion:

First, when I reached out to the team last year, I also was able to access to this website but was not sure how up-to-date the information about people and projects were. Although people can gauge this based on the list of recent publications, it can be helpful to say something like “last update: July 2020” on the first page.