Makes our immutable state explicit.

The loader is in charge of setting the newly created process's page table as the main one during the loading process.

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.

The code now properly configures the process image to match the loaded
binary segments (code, rodata, data) instead of just blindly allocating
a large chunk of dummy memory.

This enables more dynamic management of the process address space,
compared to just directly configuring the page table for major areas.

This will serve as the foundation upon which the rest of the Kernel
memory management functions will be built.