[Security] Bump jetty.version from 7.6.15.v20140411 to 9.2.25.v20180606

[dependabot-preview]

Bumps jetty.version from 7.6.15.v20140411 to 9.2.25.v20180606.

Updates jetty-jsp from 7.6.15.v20140411 to 9.2.25.v20180606

Updates jetty-webapp from 7.6.15.v20140411 to 9.2.25.v20180606

Updates jetty-server from 7.6.15.v20140411 to 9.2.25.v20180606

Updates jetty-servlet from 7.6.15.v20140411 to 9.2.25.v20180606

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[dependabot-preview]

We've just been alerted that this update fixes a security vulnerability:

Sourced from The Sonatype OSS Index.

[CVE-2011-4461] Cryptographic Issues
Jetty 8.1.0.RC2 and earlier computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.

Affected versions: ["<= 8.1.0"]