Move the GDT data to be read only data section

[kuqin12]

Description

This change moves the GDT data to be read only section.

Note that TssDescriptor symbol is also going to be manipulated. But execution-wise, this is always updated after disabling data writing. SEA validation-wise, this change will enforce a rule of TssDescriptor to be added for better validation.
 

• Impacts functionality?
• Impacts security?
• Breaking change?
• Includes tests?
• Includes documentation?

How This Was Tested

This change was tested on QEMU Q35 and booted to UEFI shell.

Integration Instructions

N/A

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.50%. Comparing base (75e5aec) to head (f992cb2).

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #381   +/-   ##
=====================================
  Coverage   0.50%   0.50%           
=====================================
  Files        142     142           
  Lines      20593   20593           
  Branches      60      60           
=====================================
  Hits         105     105           
  Misses     20483   20483           
  Partials       5       5           

Flag	Coverage Δ
MmSupervisorPkg	0.50% <ø> (ø)

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