fix: remove S2N_NO_PQ option

[kdnakt]

Resolved issues:

Resolves #4349

Description of changes:

Removed references to S2N_NO_PQ option and related codes.

Call-outs:

Testing:

I tested with the following commands.

cmake . -Bbuild \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_PREFIX_PATH=$(dirname $(dirname $(brew list openssl@3|grep libcrypto.dylib))) \
    -DCMAKE_INSTALL_PREFIX=./s2n-tls-install
cmake --build build -j $(sysctl -n hw.ncpu)
CTEST_PARALLEL_LEVEL=$(sysctl -n hw.ncpu) ctest --test-dir build

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[goatgoose]

Looks great! Thanks for cleaning this up!