Use jakarta.servlet.jsp.jstl version 2 implementation from Eclipse Glassfish

[janbartel]

For jetty-11, we have been mashing up the 1.2 version of the org.apache.taglibs implementation to shade in the jakarta.servlet api instead of the javax.servlet api. This was just a temporary fix to allow us to keep developing jetty-11 with the jakarta.servlet namespace. Note also that while our org.mortbay.taglibs-standard.jar contained the shaded classes, the -source jar we have been publishing still contains the javax.servlet api references.

The Eclipse Glassfish project has made available a 2.0 version, using the proper jakarta.servlet api. It is released under Eclipse License 2.0.

We should change to use it.

[janbartel]

Closed via #5942