Reverting activity stream patches (Bug #1316324)

Content from the following commits was reverted:

Patch 3327: 7a7673c052687558e4dd1df0286c938069ed26df
"Add activity stream block (Bug #1316324)"

Patch 3374: c538c7451be5076764ec6440a49331768a13414f
"Add likes to activity streams (Bug #1321480)"

Patch 3432: 121e90279fb8f72d81f47c5302726b6a93b7c776
"Add new parameters to the get_activity_body function (Bug #1328729)"

Patch 3434: 2e47dfb1d51368767f27316172c270cb1b8405c4
"Improvements to activity stream body helper (Bug #1328760)"

Change-Id: Id03c156a7c8c016c8dc76c998a73310ea57fe0a5
Signed-off-by: Nathan Lewis <nathan.lewis@totaralms.com>