AmpereAltraPkg: Add NVParamRuntimeDxe to read/write NVPARAM at runtime

NVParamRuntimeDxe is a proxy to access NVPARAM at runtime via UEFI variables
like NVParamOffset and NVParamValue.

UEFI Variable GUID for the runtime NVPARAM access:
0xa12544a4, 0xbcc0, 0x4b12, { 0xaa, 0x56, 0x0a, 0x2a, 0x76, 0xf1, 0x65, 0x63 }

To read a NVPARAM:
    + Write offset to UEFI variable name "NVParamOffset"
    + Read back UEFI variable name "NVParamValue"

To write a NVPARAM:
    + Write offset to UEFI variable name "NVParamOffset"
    + Write 4 bytes value to UEFI variable name "NVParamValue"

Signed-off-by: Nhi Pham <nhi@os.amperecomputing.com>