Add ttp dependency and refactor OxiAPI and NodeConfig classes

- Added `ttp` as a dependency in `pyproject.toml` and `uv.lock`.
- Updated `NodeConfig` to store model names in lowercase.
- Refactored `OxiAPI` to always create a new session and added a `close` method.
- Removed unnecessary logging in `Node` class.
- Introduced interfaces for device registration with a new `BaseDevice` class and a `register_parser` function.
- Created initial structure for device models, including a `Mikrotik` parser.

oxi/interfaces/base.py

@@ -0,0 +1 @@
+class BaseDevice: ...