RESTConf - Make certificate dependencies configurable

If the following cert/trust are not available, the application fails to startup (readiness fails). 

  collector.rcc.keystore.passwordfile: /opt/app/dcae-certificate/jks.pass
  collector.rcc.keystore.alias: dynamically generated
  collector.rcc.truststore.file.location: /opt/app/dcae-certificate/trust.jks
  collector.rcc.truststore.passwordfile: /opt/app/dcae-certificate/trust.pass

Need to support non-TLS mode as configuration option.

Either collector.header.authflag(set to 0/false) or new app-config (such enable_tls: false) to be added to support non-TLS as configuration. 

Note: Default application configuration must be TLS. Unless explicitly overridden in config to non-TLS, missing/null certificates exception must be thrown (as current behavior). When enable_tls is set to false, then application does not check for certificates and supports non-TLS mode.