WICKET-5659 Add a setting to MultiFileUploadField to not close the file uploads' streams

(cherry picked from commit 38d6b4a9c1bcf2a6ebcddeefcdf372839ca80e5c)
WICKET-5660 Throw more specific exception when a component cannot be found by ListenerInterfaceRequestHandler
WICKET-5648 CookieUtils - add #loadValues(), make #getCookie() public, properly initialize from the defaults

Remove the newly introduced CookieUtils#loadValues() method.
At http://markmail.org/message/6t5gaeb3c2h24r36 we decided to deprecate all multivalue related methods in 6.x and remove them in 7.x
WICKET-5648 CookieUtils - add #loadValues(), make #getCookie() public, properly initialize from the defaults

Deprecate all multivalue related methods.
It is not possible to deprecate #save(Strng key, String... values) because most of the time it is used by the applications as #save(key, value)