Allow registration and setting of additional kopia command arguments

[bathina2]

Is your feature request related to a problem? Please describe.
Kopia accepts many arguments to customize its use. However, Kanister only uses a subset of all these allowed arguments. It would be nice if Kanister was able to provide additional arguments to underlying Kopia arguments.

Describe the solution you'd like
I would like a mechanism to register any additional arguments required when running Kopia commands. These arguments would be set when calling Kopia comands.