Support for de-activating a datasource at runtime (application startup)

[carlesarnal]

Description

As discussed on Quarkus dev, I would like to have a way to disable datasources at runtime. Currently, this is not possible, I have tried defining different datasources for each flavor, but this still means that the datasource is created for the unused flavours, so I guess it still has some impact. I know that I can remove the unused datasource from the health checks, but I'm assuming (at least that's what I saw in my testing) that the beans are still created.

Implementation ideas

Essentially, what I'm asking for is something similar to https://quarkus.io/version/main/guides/hibernate-orm#quarkus-hibernate-orm_quarkus.hibernate-orm.active but for the datasource itself.

[quarkus-bot]

/cc @DavideD (hibernate-reactive), @Sanne (hibernate-orm,hibernate-reactive), @gavinking (hibernate-reactive), @gsmet (hibernate-orm), @mswatosh (db2)