[request] - Skip [removed] from GDPR export

[0xAnansi]

When running shreddit on a big export that already went through deletion, it still tries to fetch the comment and edit/remove it, wasting a lot of time.

A flag that adds a feature to trust that the GDPR export can be trusted when a comment has "[removed]" for content would speed the process a whole lot. This could be as simple as --skip-removed for example.