make the crate a lib which can be used by other rust code

[shenjiangqiu]

Why not add a lib.rs into bcache-tool so that other rust code can directly use the bindings. this modification will include:

1. add a lib.rs and move some mod xxx; from the bin file into the lib file.
2. create some safe bindings about {mount, device,subvolume} in lib.rs.
3. change the bin file(bcachefs.rs) to use the safe bindings( instead of currently used usafe bindings).

Is this a good idea?

[koverstreet]

Are you asking if you should do that? I'd start with something smaller.

[shenjiangqiu]

Good to here that, I was plaining to do something.