Alchemy-cat

Improved
* The README no longer recommends creating `__init__.py` next to cfg.py.
* `load_module_from_py` will check for the presence of '.' in the input path. A clear warning is given regarding rollback mode.
* When the option value of the `Param2Tune` is `Config`, copy it before assignment to ensure isolation between the option value and the config tree.

Added
* `Cfg2TuneRunner` can dynamically allocate idle GPUs. The definition of an idle GPU can be manually configured.

Improved
* Allow some `gather_metric` of `Cfg2TuneRunner` fail.

Added
* `Cfg2TuneRunner` now support auto allocate `CUDA_VISIBLE_DEVICES`.
* `Config` supports colorful printing.

Improved
* Improve compatibility with MMCV.
* Optimize the parsing logic of `rslt_dir`.