Add custom opencl

Add a custom operator implementation on OpenCL Backend.

• User can give the OpenCL code snippet to be used within an OpenCL ElementwiseKernel.

added 7 commits

• 7c72d2b2...82eba84d - 2 commits from branch master
• d480bbc6 - fix test
• 6a04c165 - Merge branch 'add-custom-opencl' of git.univ-pau.fr:vortex/hysop into add-custom-opencl
• 59647ef9 - Merge remote-tracking branch 'origin/master' into add-custom-opencl
• ca99f6e4 - fix test
• 5f8ada6a - Merge remote-tracking branch 'origin-uppa/add-custom-opencl' into add-custom-opencl

Compare with previous version

added 1 commit

• faaeb1eb - fix

Compare with previous version

enabled an automatic merge when the pipeline for faaeb1eb succeeds

merged

mentioned in commit 7ad9c181