Add support for MemUse Entropy on Windows.

[dgarske]

Description

Add support for MemUse Entropy on Windows
ZD 16422

Testing

Tested with on Windows 10 with our Visual Studio project. Adding these options to the user_settings.h:

#define HAVE_ENTROPY_MEMUSE 
#define WOLFSSL_SHA3

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[dgarske]

This PR adds a precision timer for Windows, but it should not cause this error, which leads me to suspect there could be an underlying issue:

@SparkiDev or @tmael can you please review this error: https://cloud.wolfssl-test.com/jenkins/job/PRB-generic-config-parser/1730/consoleFull ?

FAIL: scripts/openssl
wolfSSL configuration: '--enable-entropy-memuse' '--enable-opensslextra' 'CFLAGS=' 'LDFLAGS='

trying wolfSSL cipher suite ECDHE-RSA-AES128-GCM-SHA256
Matched to OpenSSL suite support
#
# ./examples/client/client -p 58519 -g -r -l ECDHE-RSA-AES128-GCM-SHA256 -v 3   "-c/var/lib/jenkins/workspace/PRB-generic-config-parser@2/wolfssl/./scripts/../certs/client-cert.pem" "-k/var/lib/jenkins/workspace/PRB-generic-config-parser@2/wolfssl/./scripts/../certs/client-key.pem" "-A/var/lib/jenkins/workspace/PRB-generic-config-parser@2/wolfssl/./scripts/../certs/ca-cert.pem" 
wolfSSL error: unable to get ctx
client failed! Suite = ECDHE-RSA-AES128-GCM-SHA256 version = 3
in cleanup
killing server: OpenSSL_RSA (58519)
killing server: wolfSSL_RSA (52748)
killing server: OpenSSL_ECDH[E]-ECDSA (60306)
killing server: wolfSSL_ECDH[E]-ECDSA (62310)
FAIL scripts/openssl.test (exit status: 1)

[tmael]

The comment indicates nanoseconds, but the returned value is in microseconds.

divide by another / 1000

or I think you can use
(word64)(count.QuadPart / freq.QuadPart * 1000000000);