Managed external services from builds

[ignasi35]

Similar to how Lagom starts/stops Cassandra and Kafka, it could be useful to register the startup/cleanup/destroy/etc... of external services to be managed by sbt or other build tools.

See https://www.playframework.com/documentation/2.6.x/SBTCookbook#Hooking-into-Plays-dev-mode
See https://github.com/lagom/lagom/pull/763/files (https://www.lagomframework.com/documentation/1.4.x/java/DevEnvironment.html#Managing-custom-services)
See https://discuss.lightbend.com/t/devhook-equivalent-for-sbt-test/586

[TimMoore]

I think this is specific to @lightbend/play-lagom (please comment/reopen if I'm mistaken)

[dwijnand]

The scope here is wide. Would be interesting to understand from @ignasi35 what problems we're trying to resolve.

For instance, if this generalises to build tools should it be a @lightbend/tooling-team issue to create an abstraction to share between maven, gradle and sbt? Or is it just to uplift the work achieved in lagom to play apps/builds, and therefore just a @lightbend/play-lagom issue?