Inconsistent segment file extension for TarGzPush and MetadataPush

Our SegmentGenerationJobRunner adds `tar.gz` extension to the segment file name.

- TarGzPush: the controller side segment upload logic removes `tar.gz`extension when copying data to deep storage. The segment file will be stored as `fileName`.
- MetadataPush: we use pinotFS to copy file from local to dst. Segment file will be stored as `fileName.tar.gz`.

It's going to be good if we can make the name convension the same. But, this will change the file name convension to the deepstorage. We should at least consider to add the config to remove the extension to have the clear migration path. (e.g. some people can start the cluster using TarGzPush and want to migrate to MetadataPush and keep the file names the same convention in the deep storage)