Docs: Update repo templates

[StephanTLavavej]

This satisfies an upcoming requirement (internal link) to update our "repo templates" from microsoft/repo-templates. I'm not exactly sure how they're going to enforce compliance, so instead of altering the files to conform to our awesome strict conventions, I'm adding binary-identical copies with exemptions from validation.

• Delete old SECURITY.md.
• Copy exactly the latest version of SECURITY.md.
• Copy exactly the latest version of CODE_OF_CONDUCT.md.
• Centralize on the newly added CODE_OF_CONDUCT.md.
• Skip validation of CODE_OF_CONDUCT.md and SECURITY.md.
  • CODE_OF_CONDUCT.md contains LF line endings.
  • SECURITY.md contains LF line endings, 1 line with trailing whitespace, and 7 lines with more than 120 columns.

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.