Removes `CODE_OF_CONDUCT.md`. Repos in the microsoft organization
will automatically link to the same code of conduct located here:
https://github.com/microsoft/.github/blob/main/CODE_OF_CONDUCT.md
Renames `LICENSE` to `License.txt` for consistency with other repos
and to match the name file sync expects.
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>