Add dependencies to pom

Adds all the external dependencies of a lib to its pom before releasing it

This fixes a major issue because previously, using one of our libs from jcenter would make the app crash at runtime if that lib had dependencies on external libraries because it wouldn't be able to know which libs are used by our lib.
yeah but we don't want to have getters and setters for these properties, we want them explicitly private, that's why this class has different getters:

```groovy
public Set<Usage> getUsages() {
  return Collections.singleton(runtimeUsage);
}
```

and

```groovy
public Set<ModuleDependency> getDependencies() {
  runtimeDependencies.withType(ModuleDependency)
}
```