Delete zipkin-ui module

[codefromthecrypt]

When we delete the zipkin-ui module, we need to also delete any references to it. Here is a list of some of these

• LICENSE - at the bottom there are notices about chosen and dagre-d3 which should be removed. Fixes accidental license headers on vendored javascript libraries #2568
• pom.xml - license exclusions in both the license and rat plugin configuration

[codefromthecrypt]

It turns out that we can delete this a lot sooner than we expected, solving the problem by using an archive repo instead of constantly building the same code here: https://github.com/openzipkin/zipkin-classic/

once #2603 is merged we should do the following in one PR (@zeagord claimed the honors on this)

• move zipkin-ui/testdata to zipkin-lens
• remove exclusions in pom.xml remove when deleting zipkin-ui #2569
• remove recursively the zipkin-ui directory
• remove the following from the LICENSE file

This product contains a modified part of Chosen, distributed by Harvest:

  * License: MIT
  * Homepage: https://github.com/harvesthq/chosen

This product contains a modified part of Dager-D3, distributed by Dagre:

  * License: MIT
  * Homepage: https://github.com/dagrejs/dagre-d3

[jorgheymans]

zipkin-ui module was deleted.