UefiCpuPkg: Create CpuPageTableLib for manipulating X86 paging structs

UefiCpuPkg: Create CpuPageTableLib for manipulating X86 paging structs

The lib includes two APIs:
* PageTableMap
  It creates/updates mapping from LA to PA.
  The implementation only supports paging structures used in 64bit
  mode now. PAE paging structure support will be added in future.

* PageTableParse
   It parses the page table and returns the mapping relations in an
  array of IA32_MAP_ENTRY.

It passed some stress tests. These test code will be upstreamed in
other patches following edk2 Unit Test framework.

Signed-off-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>