[UWS,TAP] Externalize `org.json`.
`org.json` was included in the sources of UWS-/TAP-Lib because of a manual small correction. This is no longer needed. So this library is now a dependency (included in the generated JAR). This has also been upgraded to the version of August 2018. _This commit aims to reproduce the original content of the Pull Request #38 by @vforchi ._