Add new API options to display a banner in the client.

bbb-common-web/build.sbt

.../main/java/org/bigbluebutton/api/ParamsProcessorUtil.java

...b/src/main/java/org/bigbluebutton/api/domain/Meeting.java

bigbluebutton-client/branding/default/style/css/V2Theme.css

bigbluebutton-client/src/org/bigbluebutton/core/model/Me.as

...button-client/src/org/bigbluebutton/core/model/Meeting.as

...rc/org/bigbluebutton/main/model/users/EnterApiResponse.as

...ent/src/org/bigbluebutton/main/model/users/JoinService.as

...ent/src/org/bigbluebutton/main/model/users/UserService.as

...rc/org/bigbluebutton/main/views/MainApplicationShell.mxml

...-client/src/org/bigbluebutton/main/views/MainToolbar.mxml

...rs/org/bigbluebutton/web/controllers/ApiController.groovy