Update Server.pm

render_json was removed in Mojolicious 4.0
Update Service.pm

render_json was removed in Mojolicious 4.0
Update ServerGroup.pm

render_json was removed in Mojolicious 4.0
Update Hardware.pm

render_json was removed in Mojolicious 4.0
Merge pull request #1 from reneeb/master

First round of render_json() -> render( json => )