Add a test to check URP add and delete conflict

[progier389]

The goal is simply to add some test about URP conflict handling in the ADD - DEL because I got some surprise when dealing with conflict entries.
One of the test is performing ADD, SYNC TO REPLICA A, SYNC TO REPLICA B, DEL and test all orders of that sequence between 3 replica
Note: there are about 5700 orders and the test spend 6 days
A second test tries to clean conflict entry in a weird case (crossed entries that should theoretically not happen but was sometime seen anyway)

Theses tests requires URP_VERY_LONG_TEST environment variable to run.

Note:
Initially I though about trying all the order of single actions on the 3 replica but that is more than 1M orders and 3.5 years of test ! -;)