Followups to kopia#3655

* wrap fs.Reader
* nit: remove unnecessary intermediate variable
* nit: rename local variable
* cleanup: move restore.Progress interface to cli pkg
* move cliRestoreProgress to a separate file
* refactor(general): replace switch with if/else for clarity
  Removes a tautology for `err == nil`, which was guaranteed
  to be true in the second case statement for the switch.
  Replacing the switch statement with and if/else block is clearer.
* initialize restoreProgress in restore command
* fix: use error.Wrapf with format string and args


Simplify SetCounters signature:

Pass arguments in a `restore.Stats` struct.
  `SetCounters(s restore.Stats)`
Simplifies call sites and implementation.
In this case it makes sense to pass all the values
using the restore.Stats struct as it simplifies
the calls.
However, this pattern should be avoided in general
as it essentially makes all the arguments "optional".
This makes it easy to miss setting a value and simply
passing 0 (the default value), thus it becomes error
prone.
In this particular case, the struct is being passed
through verbatim, thus eliminating the risk of
missing a value, at least in the current state of
the code.

Followups to kopia#3655

* wrap fs.Reader
* nit: remove unnecessary intermediate variable
* nit: rename local variable
* cleanup: move restore.Progress interface to cli pkg
* move cliRestoreProgress to a separate file
* refactor(general): replace switch with if/else for clarity
  Removes a tautology for `err == nil`, which was guaranteed
  to be true in the second case statement for the switch.
  Replacing the switch statement with and if/else block is clearer.
* initialize restoreProgress in restore command
* fix: use error.Wrapf with format string and args


Simplify SetCounters signature:

Pass arguments in a `restore.Stats` struct.
  `SetCounters(s restore.Stats)`
Simplifies call sites and implementation.
In this case it makes sense to pass all the values
using the restore.Stats struct as it simplifies
the calls.
However, this pattern should be avoided in general
as it essentially makes all the arguments "optional".
This makes it easy to miss setting a value and simply
passing 0 (the default value), thus it becomes error
prone.
In this particular case, the struct is being passed
through verbatim, thus eliminating the risk of
missing a value, at least in the current state of
the code.