Make copying to efs using rsync (or similar) instead of cp

[Hi-Fi]

Currently copying of externals take around 3 mintues, as runner copies full Node16 and Node20 also.

To save that time, either parallel copy (recommended by https://repost.aws/knowledge-center/efs-troubleshoot-slow-performance) or some better appoach (like shared externals) could be used.

Copying: https://github.com/Hi-Fi/runner-container-hooks/blob/aws/packages/ecs/src/hooks/prepare-job.ts#L208-L213

With those options shared externals doesn't help, as things will be overwritten according settings.

One option for rsync: https://www.npmjs.com/package/rsync2

[Hi-Fi]

Relates to actions/runner-container-hooks#168.

Solved by building checksum of externals, and comparing it before doing copy. Also moved externals to own volume so those are easier to share between container.

See: https://github.com/Hi-Fi/runner-container-hooks/blob/azure/packages/aca/src/hooks/prepare-job.ts#L150-L169