TLS Registry: provide a TLS configuration called javax.net.ssl having truststore set in the same way as default SunJSSE provider

[ppalaga]

Description

User may want to use the default Java truststore that is usually available under $JAVA_HOME/lib/security/jssecacerts, $JAVA_HOME/lib/security/cacerts or overridden throw javax.net.ssl.trustStore system property.

To make this use case easier, we should introduce a reserved javax.net.ssl TLS configuration name with the following properties:

• Users can use javax.net.ssl as a value for various *.tls-configuration-name options, such as quarkus.http.tls-configuration-name
• Users do not need to define that named TLS config by themselves
• A TLS configuration with name javax.net.ssl would be created on demand by the TLS registry extension

[quarkus-bot]

/cc @radcortez (config)

[ppalaga]

I narrowed the scope to cover only the default truststore.