create env_ccpsynerbi.ps1 and .bat

[KrisThielemans]

We need to create environment files for Windows, ideally supporting Powershell and bat.

Here's what I need on my system for the .PS1 file

$install="C:\Users\krisf\Documents\devel\buildVC\SIRF-SuperBuild\INSTALL"
 $Env:Path = "${install}\bin" + ";" + $Env:Path
 $Env:Path += ";${install}\FFTW"
 $Env:Path += ";c:/local/boost_1_74_0/lib64-msvc-14.2/"
 # need to be forward slashes 
 $Env:SIRF_PATH = "C:/Users/krisf/Documents/devel/buildVC/SIRF-SuperBuild/sources/SIRF"
 $Env:PYTHONPATH = "${install}\python"
 $Env:MATLABPATH = "${install}\matlab"
 $Env:MATLABPATH+=';C:\Users\krisf\Documents\devel\buildVC\SIRF-SuperBuild\sources\SPM'
 $Env:Path += ";c\Program Files\MATLAB\R2020b\bin\win64;c:\Program Files\MATLAB\R2020b\extern\bin\win64"

Obviously, these have to be determined from internal variables.

[KrisThielemans]

See https://github.com/SyneRBI/SIRF/pull/853/files#r571159815 for / vs\