Optimize snippet build

[Shiranuit]

What does this PR do ?

This PR tries to reduce the snippet testing time, by compiling every snippets scenario in one executable instead of compiling them each time and spending time in compilation between each tests

This is a Proof of Concept and might not be adopted.

The goal is to compile each snippets inside one file, the way this is achieved is by creating a function for each snippet scenario
and the main function is calling the appropriate function based on an environment variable.
This reduces compilation time to one time instead of having to relaunch the gradle daemon for each step.

The testing time has been reduced by 30%.

Another way to reduce testing time is to launch tests in parallel, some work is currently done to test how this could be achieved

[Aschen]

I'm in to test this new approach 👍