Rdlm-py

- doc update

- add `resource_get_all()` and `resource_get_all_locks()` methods
- add three new cli tools to interact with the RDLM server
- little bugfixes and typo

- doc update

- introduce a `RDLMContextManagerFactory`object
- introduce two cli tools to interact with the RDLM server
- upgrade requirements
- typos and styles fixes

- `lock_acquire()` can return an RDLMClientException
- `RDLMLockServerException` is renamed to `RDLMServerException`

- light refactoring
- new methods :
- `lock_get()`
- `lock_resource_delete()`
- `lock_resource_delete_all()`