Use load_and_authorize_resource in versions controlller
Add conference specifc route to revision history page
Users with role can view revision_history only for the versions they have access to
Handle versions where conference_id is not set (records before papertrail was introduced)
We are using `paper_trail` gem, which saves data in database table
versions. It has a native way to search in the versions records,
using `where_object()` and `where_object_changes()`. They are broken,
under certain conditions. We changed them to a manual `where()`.
To test this case we need: an Event with ID 1, an Event with ID 2, and
a commercial with ID 1, for event with ID 2 - obviously the numbers
could be different as long as there is this matching of IDs. Before
this was made wit ha expect, which would make the test fail if this is
not the case. But this is actually the test case, not what we want to
test, so I moved to the `let`.
This was also the case why one of the test was broken after we change
how the database is cleaned in:
https://github.com/openSUSE/osem/pull/1541
I also remove the feature test, as this should be tested in a
controller test.
There is a known issue in paper_trail that whenever we Query the
'versions.object' column it evaluates inconsistent results for numeric
values due to limitations of SQL wildcard matchers against the
serialized objects. So to fix this issue I have manually formed the where
query instead of using where_object and where_object_changes. I have
also added test for the same.
Fixes#1307
