Remove submodules
Squashed 'core/' content from commit 3cada65

git-subtree-dir: core
git-subtree-split: 3cada65d5a5157f48a93bb848c684bd07ecfc41e
Merge commit 'e6d9c06196d9c1933d9cc6ca7c9d8c0727b547e5' as 'core'