Includes:
- Job and CoroutineScope extensions for Lifecycle and LifecycleOwner
- Transitive dependency to kotlinx-android artifact
- Tests and test supporting code
- Documentation
- Entry in binary-compatibility-validator build.gradle file

…to LifecycleDefaultScopes.kt

That is to prevent class initialization in case they are not used.

This makes the intent more explicit

Because the maps are just a best effort cache, we don't need the
concurrency safety that ConcurrentHashMap offers.

If the scopes or jobs are accessed concurrently, there may be multiple
created instances, but eventually, an attempt to remove them from the
caching map will always be performed when the lifecycle is destroyed.

This allows to support use cases like creating a scope active while
STARTED from an Activity onStart() method.

Replacing mutableMapOf() with ConcurrentHashMap().
Regular HashMap could lead to an infinite loop in some cases where the
map would be accessed concurrently.