Enh/strip py suffix from bins

Debian policy states that system-wide installed scripts should not carry
implementation specific suffixes (.py in this case).  That is done for
few reasons:

- they are useless in this context
- user should not care what they are implemented in if they are scripts
- their names should not change happen you decide to reimplement them in
  another language (unlikely here)

so I would recommend to strip suffixes from those and simply rely on
shebangs