Simplify: skip py27, no conda-forge, pip pywps

## Description

Simplify the template:
* skip support for python 2.7
* add support for python 3.6, 3.7, ...
* conda-forge is troublesome for stabilitiy, avoid it.
* install pywps via pip

## Environment

* Cookiecutter version used, if any:
* Python version, if any:
* Operating System:

## Steps to Reproduce


## Additional Information
