Upgrade to latest Jetty version

[dpvelasquez]

Jetty 9.4.14.v20181114 has security vulnerabilities where the server is vulnerable to XSS conditions.

https://www.cvedetails.com/cve/CVE-2019-10241/

[findepi]

From that CVE

... the server is vulnerable to XSS conditions if a remote client USES a specially formatted URL against the DefaultServlet or ResourceHandler that is configured for showing a Listing of directory contents.

I suppose we don't use DefaultServlet nor ResourceHandler configured for showing a Listing of directory contents.
@electrum do we?

(This is not to say we shouldn't upgrade. I'm just trying to understand the situation better.)

[wendigo]

Completed. Please close @electrum