Move collections/ and sync/ (including sync.h) out of shared/ #37
Description
At some point move the collections library and the sync library into libk or the kernel instead of putting it in shared (as "collections/" or "sync/" is a very generic name and might unironically be used in some projects so I feel like its better to not reserve it) and removing all the dependencies on things like list.h and instead have them implement it themselves or copy the header.