Add support for replication across multiple versions

[PrzemekMalkowski]

I would absolutely love to see the functionality like:
dbdeployer deploy replication --master-ver=5.6.35 --slave-versions="5.6.40,5.7.22"

[datacharmer]

It should be doable. It only requires some time to avoid breaking other functionalities.

Specifically, this feature must work together with :

• the main definition of a version (dbdeployer deploy replication 5.6.41). This could be fixed by using the main version (5.6.41 in the previous example) as the master version.
• the emergency definition of the working version (dbdeployer deploy --binary-version=xxx ...).

Another issue could be different topologies that don't use slaves, such as group replication or multi-source. I don't even know if GR would work with servers of different versions.

Furthermore, this feature may also require that we change the way we initialize slaves, as some versions use options that are not available in previous ones. For example, initialization commands for 8.0.x slaves will fail for 5.7.x slaves. A possible workaround would be to only allow this feature where the slaves versions are higher than the master.

Anyway, I have several issues to tackle before this one. I am open to suggestions (and to pull requests!)

[datacharmer]

dbdeployer version 1.26.0 implements replication between sandboxes. See Replication between sandboxes.
Using this feature, you can deploy sandboxes from various versions, and start replication between them.

[datacharmer]

In dbdeployer 1.27.0 there is a cookbook example of cross-version replication.

Run the following:

dbdeployer cookbook list
[...]

dbdeployer cookbook create replication_multi_versions

Then look at recipes/replication-multi-versions.sh and eventually run the example by providing three versions on the command line.