Implement proper title memory allocation

[mborgerson]

Currently the memory allocation works by just giving out memory in increasing order. This works with most of the NXDK samples because they simply make a few allocations at startup and never free, but this would fail spectacularly if any title tried to actually free/alloc. Thus, a proper memory allocator is needed.

• [x] Support tracking of physical memory
• [x] Support allocation of contiguous and non-contiguous chunks of physical memory
• [x] Support mapping physical memory into the virtual address space

Implement associated functions:

• [ ] MmAllocateContiguousMemory
• [x] MmAllocateContiguousMemoryEx (Partial)
• [ ] MmAllocateSystemMemory
• [ ] MmClaimGpuInstanceMemory
• [ ] MmCreateKernelStack
• [ ] MmDeleteKernelStack
• [ ] MmFreeContiguousMemory
• [ ] MmFreeSystemMemory
• [ ] MmGetPhysicalAddress
• [ ] MmIsAddressValid
• [ ] MmLockUnlockBufferPages
• [ ] MmLockUnlockPhysicalPage
• [ ] MmMapIoSpace
• [ ] MmPersistContiguousMemory
• [ ] MmQueryAddressProtect
• [ ] MmQueryAllocationSize
• [ ] MmQueryStatistics
• [ ] MmSetAddressProtect
• [ ] MmUnmapIoSpace
• [x] NtAllocateVirtualMemory (Partial)
• [ ] NtFreeVirtualMemory

It may be possible to leverage parts of the Linux kernel to implement this. Recommend an earlier kernel version for simplicity.

[MayeulC]

Interesting resources: https://news.ycombinator.com/item?id=18180940 https://wiki.osdev.org/Memory_Allocation