[keycloak-dev] Resource versions for SNAPSHOTS builds

When running SNAPSHOT builds the resource version contains -snapshot, but doesn't get updated. This is annoying since stale resources are cached. To work around this I've sent a PR to replace -snapshot with the build time [1]. Further, When KeycloakServer is ran directly from the IDE the build time isn't updated so I made it change the build time to the execution time when not ran from within Maven [2]. [1] https://github.com/keycloak/keycloak/pull/4287/files#diff-54e8a0187ed2030... [2] https://github.com/keycloak/keycloak/pull/4287/files#diff-04c94b7f1ce8f7d...