Consolidates redundant boilerplate on cloning at the beginning of each tutorial
Instructs users to use git clone --recursive --shallow-submodules --single-branch in order to reduce the size of the cloned submodules (particularly PelePhysics, which has a hefty history from reformatting large mechanisms) and avoid cloning unnecessary branches (relates to #307)
clang_formatgit clone --recursive --shallow-submodules --single-branchin order to reduce the size of the cloned submodules (particularly PelePhysics, which has a hefty history from reformatting large mechanisms) and avoid cloning unnecessary branches (relates to #307)