Create test sets from CLI

[mmabrouk]

Is your feature request related to a problem? Please describe. We would like to be able to manage and create test sets from CLI

agenta testset
agenta testset list: List testsets in the app.
agenta testset add --file_name mytestset.csv --testset_name mytestsetname: Upload a file and create a testset.
agenta testset remove --testset_id: Remove an existing testset.

#991 is a requirement for starting this (otherwise we would need to write the client SDK)

[poerty]

@mmabrouk Can I work on this?

[mmabrouk]

of course :)