Consider replacing libcurl-gnutls with libcurl-openssl

[bluecmd]

Hi,

Background: sonic-net/sonic-buildimage#14351

I tried compiling sonic-mgmt-framework with libcurl4-openssl instead of libcurl4-gnutls and things seem to work fine for me. Maybe we should consider dropping gnutls and using libcurl4-openssl as the rest of SONiC?