Extend Lockfile checker and generator

As a follow up to:
- https://github.com/nexB/dependency-inspector/issues/2

Here are the next candidates:

- Java:
- [ ] Maven https://github.com/nexB/dependency-inspector/issues/6
- See also https://github.com/search?q=maven+dependency+tree&type=repositories
- Note that the `mvn dependency:tree` command would typically process all pom.xml in the codebase at once, and would generate one tree for each each pom.xml
- a good set of args to run the command would be : `mvn dependency:tree -DoutputFile=maven-dependency-tree.lock -DoutputType=graphml` and optionally with`-Dmaven.test.skip=true` and `-DskipTests` to skip tests, or various other options (such as scope) to filter the tree. See https://maven.apache.org/plugins/maven-dependency-plugin/tree-mojo.html
- [ ] Gradle https://github.com/nexB/dependency-inspector/issues/9
- See https://docs.gradle.org/current/userguide/dependency_locking.html
- https://github.com/GeekMasher/gradle-lock-dependency-submission-action
- Other:
- [ ] Create composer lock file with `composer`
- [ ] Create Ruby lock file with `bundler`
- [ ] Create go.sum lock file with `go` (though this should be standard by now)
- [ ] Create cargo/Rust lock file
- [ ] Create Dart/pub lockfile