Add 5 new new columns to event_log table make searching over the
data easier and also record the id of any parent/related info as well

Eg, if one deletes an image block from a page we now record:
id - the event id
resourceid - the block id
resourcetype - the blocktype, eg image
parentresourceid - the id of the parent, eg view id
parentresourcetype - the type of parent, eg 'view'

Because we would not be able to find related view info from just the
block id anymore.

Also added the ability to index and search over event information in
elasticsearch search type event_log

Change-Id: I280c1c75c35a6c58f42d8acb36cf5c24c70b902d
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>