Flyway: Add ignoreMissingMigrations flag

[expeditioneer]

What version of Flyway are you using?

4.0.3

Which client are you using? (Command-line, Java API, Maven plugin, Gradle plugin, SBT plugin, ANT tasks)

Java API

What database are you using (type & version)?

h2 1.3.175

What operating system are you using?

Windows

What did you do?

(Please include the content causing the issue, any relevant configuration settings, and the command you ran)
Removed already applied migration script

What did you expect to see?

Flyway ignoring the missing, but already applied migration

What did you see instead?

Validate failed: Detected applied migration not resolved locally

This was maybe introduced by accident with #988.

Possible solution:
Check also for the MigrationState.MISSING SUCCESS in MigrationInfoImpl::validate()

[axelfontaine]

The solution here would be to have something like an ignoreMissingMigrations flag, set to false by default. You could then set it to trueto get the behavior you want.

[gsaslis]

👍 need this too

[sdrzazga]

+1

[axelfontaine]

Duplicate of #1352