Improve storage error handling for config metadata during bootstrap

It was seen from one of the customer environments that storage error during bootstrap can cause partial config metadata to be written to MetadataStore file which makes it unusable.

Following improvements can be done:
1. Log all storage errors in gometa for better troubleshooting.
2. Handle storage errors during bootstrap to fail completely instead of writing partial metadata file.
3. Write all the config entries in a single transaction to storage so its all or none.