Issue 56: logging and checkpoint directories

[anhtu293]

General description of your pull request with the list of new features and/or bugs.

• New feature 1 : Structure directory for logging and checkpoint during training
• New feature 2: Since now, there is a config file alonet_config.json created in ~/.aloception which defines the default directory to save log and checkpoint during training. If the file does not exist, user can create it during the first training.
• New feature 3: We can also have use the different path for logging and checkpoint as in alonet_config.json by using --log_save_dir path_to_dir and --cp_save_dir path_to_dir.

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This pull request includes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

[Data-Iab]

@anhtu293 target branch should be dev