CMake Fetchcontent instead of submodules

[CedricGuillemet]

To be more consistent with BN, easier updates to different BabylonNative version and prepare the work to use prebuilt BN.

• fix issue with arcore. "windows build agents don't support the path lengths required for initializing arcore dependencies". module is not fetched anymore on Windows.
• Remove code to update submodule in gulp.js , tools.js andjobs .yml
• Code to update submodule to the latest in gulp.js is removed. Now change the commit id in shared/CMakeLists.txt

Notes:

• Using fetch populate and add_subdirectory after instead of makeAvailable because of binary directory differences of platforms. This is something I'll try to revisit in upcoming PRs.
• There is a check to not populate multiple times in shared/CMakeLists.txt. With iOS build, I got an error saying it's already populated. I'm sure why this happens.

This change needs BabylonJS/BabylonNative#1312

[bghgary]

Looks okay to me