MimeType is not the same as Content-Type

In CordovaResourceApi (and maybe elsewhere) mimetype is set with the value of the header "Content-Type" but when "Content-Type" contains the charset (ex: "text/html; charset=utf-8") the mimetype is incorrect and lead to problems when loaded as WebResourceResponse.

ex: webpages loaded as raw HTML

"Content-Type" should be splitted at the ";"