Mock Jwt Test Support and Jwt.Builder Polish

Simplified the initial support to introduce fewer classes and only the
features described in the ticket.

Changed tests to align with existing patterns in the repository.

Added JavaDoc to remaining public methods introduced for this feature.

Issue: gh-6634
Issue: gh-6851

test/spring-security-test.gradle

@@ -7,8 +7,8 @@ dependencies {
 	compile 'org.springframework:spring-test'
 
 	optional project(':spring-security-config')
-	optional project(':spring-security-oauth2-resource-server')
 	optional project(':spring-security-oauth2-jose')
+	optional project(':spring-security-oauth2-resource-server')
 	optional 'io.projectreactor:reactor-core'
 	optional 'org.springframework:spring-webflux'