Adding mount command for Windows and Linux

[precurse-bf]

This PR adds mount command support for Windows and Linux as per #93 . This was a collab between me and @RafBishopFox.

Windows support was added by @RafBishopFox and Linux support added by me.

Output looks like the following:

Linux:

sliver (PANICKY_SCULPTURE) > mount

 Source                     Mount Point                                   Mount Root                                                                                                               Filesystem Type       Options                           Total Space 
========================== ============================================= ======================================================================================================================== ===================== ================================= =============
 fuse-overlayfs             /                                             /                                                                                                                        fuse.fuse-overlayfs   rw,nodev,noatime                  606.80 GB   
 proc                       /proc                                         /                                                                                                                        proc                  rw,nosuid,nodev,noexec,relatime   0 B         
 tmpfs                      /dev                                          /                                                                                                                        tmpfs                 rw,nosuid                         64.00 MB    
 sysfs                      /sys                                          /                                                                                                                        sysfs                 ro,nosuid,nodev,noexec,relatime   0 B         
...omitted for brevity...

Windows:

[rkervella]

Just one remark on the Windows side of things that may require some changes to the protobuf message and overall parsing.
Looks good otherwise, thanks @RafBishopFox and @precurse.