[vali] extend the sessionmanager to manage processes

[Meulengracht]

Add support for starting threads with a given memoryspace. Add interface for managing address spaces. Determine which systems are per-process and find new places for them.

• Convert address spaces to handles
• Extend the thread creation to support supplying an address space
• Create an interface for address spaces
• Extend the pe-loader to be sharable between kernel and userspace
• Create process functionality in sessionmanager
• Define the process interface for the sessionmanager
• Remove all process functionality from kernel that is unneeded.
• Update all references to use sessionmanager instead