Update the Plugin Manager Updates View with more Info about incompatible...

Update the Plugin Manager Updates View with more Info about incompatible dependencies and change CSS classes (#4299)

* add information about incompatible plugin updates

* use alert-danger CSS class

* revert stripping whitespaces

* Update core/src/main/resources/hudson/PluginManager/_table.css to include a line brak at the end

Co-Authored-By: Oleg Nenashev <o.v.nenashev@gmail.com>

* use separate text for list of incompatible plugins

* restore and deprecate style.css

* make better use of caching