[TASK] reformat code
[FIX] introduce interface and abstract class for minifier service, improve CGL and add use statements
[FIX] add use statements
[TASK] improve EM options text
[FEATURE] add Wikimedia's JavaScriptMinifier
[TASK] add some information about the minifiers
[TASK] fix JSMin+ naming in EM options
[BUGFIX] fix JavaScriptMinifierService class name