Rewriting ssl validation to try multiple certs found in paths

Previously, the function checked only for a single CA root cert, however
some distributions may have multiple certs in a directory. This will now
try any .crt or .pem file contained within several common paths for
each platform.

Fixes #6412
Remove unused code from get_ca_certs() function
Adding validate_certs to all modules that use fetch_url
Remove validate_certs parameter from fetch_url calls
Compile ca certs into a temp file to reduce number of attempts

For those who may have a large number of certs found, this can reduce
the number of ssl connections attempted.