Bug 1804243: timeline: show correct version of a plan block

saves in version

for plans:
 title
 description
 tags

for tasks:
 task title
 description
 completion date
 completed status(yes/no)
 tags

behatnotneeded
Change-Id: Ib09cf4b8718f1180cb5f021bc532659db7f39647
(cherry picked from commit b829af50)