Kernel: Big commit. Rewrite ELF loading code

We now load ELF files to VirtualRanges instead of using kmalloc.
We have only a fixed 1 MiB kmalloc for big allocations and this
allows loading files even when they don't fit in there.

This caused me to rewrite the whole ELF loading process since the
loaded ELF is not in memory mapped by every process.

Virtual ranges allow you to zero out the memory and to copy into
them from arbitary byte buffers.

kernel/include/kernel/Memory/VirtualRange.h

@@ -23,11 +23,15 @@ namespace Kernel
 		size_t size() const { return m_size; }
 		uint8_t flags() const { return m_flags; }
 
+		void set_zero();
+		void copy_from(size_t offset, const uint8_t* buffer, size_t bytes);
+
 	private:
 		VirtualRange(PageTable&);
 
 	private:
 		PageTable&				m_page_table;
+		bool					m_kmalloc { false };
 		vaddr_t					m_vaddr { 0 };
 		size_t					m_size { 0 };
 		uint8_t					m_flags { 0 };