Obsolete in html5 and also was breaking the message sanitizer

 - verify presentation and meeting id formats
 - construct presentation file path making sure that they are valid
 - add "downloadable" flag to check if presentation can be downloaded or not
 - collect presentation upload errors so we can send to the client in the future

 Made a mistake of defining param twice

 Make bbb-web bind to localhost

Turn off png generation as we don't use it.

 - addjust timeouts

 - setup number of processing threads

 - log upload captions params