Dry Runs feature support

[olsh]

Flyway has Dry Runs feature.
It would be beneficial to have the feature in Evolve too.

[lecaillon]

I'm currently working on a improved version of the evolve info command #123 where you can view the actual state of the database and determine migrations that need to be applied.
I think it is a first good step to a feature like the dry run.

[lecaillon]

Finally, this feature will be available in Evolve 3.0 as an option : TransactionMode.RollbackAll.
The idea is to give the possibility to manage Evolve transaction scope. In this case, run all the scripts of the migration and then rollback them in order to validate/preview the changes Evolve will make to the database.

[lecaillon]

See #210 for the TransactionMode.CommitAll feature
I will publish soon Evolve 3.0.0-alpha5 to be able to test it before I release it. Feel free to give feedback