Feature/add update delete support

[ygnuss]

We listen to the following binlog events:

1. Inserts
2. Updates
3. Deletes

For updates and deletes we use ALTER TABLE command. We cannot use mempool to optimize.

The main issue seems to be CH is not able to handle all the update events. CH after applying mutations, before marking them as finished, checks if there are other pending mutations. In our case, mutations are constantly arriving so CH always find new pending mutations so never marks the applied mutations as finished. The number of mutations increases flooding of files the HDD and, if using replication, collapsing the zookeeper because it has too many entries on the mutations znode.

We use this approach for the BeBanjo PoC and it works, during a time, because didn't use replication. After a couple of weeks, we start having issues with the mutation files.

We have discarded this approach in favor of using inserts for updates and deletes and handling mutations the same way ITX does.