Add the long description for bar files

Idea review. Thank you for taking the time to raise this suggestion, which for now we are placing into status Not Under Consideration, pending further feedback ... Unfortunately it wasn't clear from the suggestion whether the desire for a description field relates to Message Flow level, Application level ... or to be attached to the BAR file itself? Given that a message flow has description fields, which are also reported back through the admin REST API (and displayed in both Toolkit and WebUI), we assume that the request doesn't relate to flows? For application-wide description fields, we don't currently have a natural artifact file to which we would attach the property (conceptually we can consider the application like a "folder" or directory on the system), but this aspect of implementation could potentially be overcome if this was the intention. Regarding the third possibility of a BAR file, we would not be in favour of carrying a description field to be persisted in the runtime on the BAR file ... The BAR file is sometimes described as a "carrier bag" which has help and meaning in moving artifacts from source to server, but is not a concept which is persisted in the runtime - once its artifacts are deployed (which could be iterative) the BAR file is "discarded". As mentioned, for now we are returning the idea but please feel free to add further information if we've misunderstood and we can comment further.