Use block.MetaFetcher for all meta json syncs

[bwplotka]

This is to make sure we have consistent meta.json fetch logic for all command (e.g graceful partial block support)
AC:

• Use block.MetaFetcher inside verify command
• Use block.MetaFetcher inside bucket command

[daixiang0]

I would like to take this:)

[bwplotka]

It's also a good first task for @khyatisoneji

She is our student as a part of CNCF Community Bridge program, and it sounds like a good introduction if you don't mind @daixiang0

[daixiang0]

Never mind, welcome @khyatisoneji