Add support for Flyway "missing migrations"

[knutwannheden]

Description
Flyway can be configured to ignore missing migrations (see FluentConfiguration#ignoreMissingMigrations(boolean) for details). This configuration is not currently exposed by the Quarkus Flyway extension.

Implementation ideas
Add a new boolean-typed quarkus.flyway.ignore-missing-migrations configuration property (defaulting to false as in Flyway).

[gsmet]

@knutwannheden want to give it a try?

[knutwannheden]

@gsmet Yes, why not. I will try to take a look later this week.

[gsmet]

A good example would be https://github.com/quarkusio/quarkus/pull/10732/files but I think the callbacks probably need to be build time config.