Refactored save, load, and from_checkpoint to support zip format by d… (#1185)

* Refactored save, load, and from_checkpoint to support zip format by default

Signed-off-by: Charlelie Laurent <[email protected]>

* Added examples to docstrings + minor improvements in state_dict loading

Signed-off-by: Charlelie Laurent <[email protected]>

* Reverted order of checkpoint format checks

Signed-off-by: Charlelie Laurent <[email protected]>

* Added option to save checkpoint with legacy tar-based format

Signed-off-by: Charlelie Laurent <[email protected]>

* Improved IO resource management when loading checkpoint from zip archive + safer temporaruy file creation

Signed-off-by: Charlelie Laurent <[email protected]>

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Signed-off-by: Charlelie Laurent <[email protected]>
Co-authored-by: Oliver Hennigh <[email protected]>
Co-authored-by: Corey adams <[email protected]>

Author: 3 people