Fixes and refactor for static ephemeral key support

[dgarske]

• Added x448 static ephemeral support.
• Refactor of the static ephemeral key internals and addition of mutex protection.
• Fix for possible use after free if loaded in CTX and used in SSL then reloaded in CTX.
• Fix to allow calls to get TLS session random even if wolfSSL_KeepArrays has not been called.
• Eliminate EIGHTK_BUF use in asn.
• Cleanup uses of 0 in set_verify for callback.

[anhu]

Got this building on Linux.

./configure --enable-sniffer --enable-all  CFLAGS="-DWOLFSSL_DH_EXTRA"

src/sniffer.c: In function ‘SetupKeys’:
src/sniffer.c:2722:12: error: ‘ret’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
 2722 |         if (ret == 0 && keyBuf == NULL) {
      |            ^

make check also fails:

FAIL: scripts/ocsp.test
FAIL: scripts/ocsp-stapling.test
FAIL: scripts/ocsp-stapling2.test
FAIL: scripts/unit.test

[SparkiDev]

Configuration fails unit.test:
./configure --enable-sniffer --enable-curve448

[dgarske]

Configuration fails unit.test:
./configure --enable-sniffer --enable-curve448

@SparkiDev : Thank you for finding that! Very good bug report with this PR. Ready for another review pass once Jenkins is done.