borg2: repo-list: add --from-borg1 option

[ThomasWaldmann]

Users may want to list their old repo before using borg transfer, so guess we need that option there also.

[ThomasWaldmann]

As a workaround, borg transfer --dry-run --list ... can also be used (if looking at the old repo's archives was desired in a transfer context).

[alighazi288]

Could you please provide any additional details or pointers on the expected implementation and output format? Thanks!

[ThomasWaldmann]

Maybe let rather me fix that, it can get rather complicated while working with the 2 flavours of borg repos and the related code. Maybe we don't even need this and can live with the workaround.

[alighazi288]

Understood. Thanks!