CustomTask should use Gradle's NamedDomainObjectContainer or NamedDomainObjectSet

[vlsi]

See https://github.com/dropbox/AffectedModuleDetector/pull/130/files#diff-6b5be434aa24824fb2973ce77a9dcda484db988e76842f367fb289129851c318R44

var customTasks = emptySet<AffectedModuleConfiguration.CustomTask>() would be better migrated to DomainObject APIs.
Here's a relevant article: https://blog.mrhaki.com/2016/02/gradle-goodness-create-objects-with-dsl.html

[Evleaps]

Hey! Thank you! I do it later.