Fix clientdir path conversion in import.py
Use long-args for passing to Java

Inserting a `=` between short args leads to odd
naming constructors like `=foo` for an image. By
using the long args, the logic on this branch
works fine.
Correct short-arg parsing

Other short args like `-l` don't have a long-form.
The "fix" in this branch to use `--name=value` is
invalid there. The use of a tuple in the map of
names defines which arguments will have this op
applied.
Use fixture rather than multiple parametrize for naming arguments

This commit reduces the overall number of tests by testing --plate_name and --plate_description arguments for plate imports only.