Add pykmip-client executable so we can run kmip client

[Soromeister]

Exactly as the title says, installing the package gets you only the server, not the client. I am interested in just the client itself to run tests against an already existing kmip server:

pipx list
venvs are in /Users/user/.local/pipx/venvs
apps are exposed on your $PATH at /Users/user/.local/bin
manual pages are exposed at /Users/user/.local/share/man
   package pykmip 0.10.0, installed using Python 3.13.1
    - pykmip-server
    - pykmip-client // This is missing and needs to be added