Way to MyFaces 2.3-next

I (and other commiters) spend many hours to prepare the MyFaces codebase for the upcoming version 2.3-next during the last months, which will be MyFaces 4.0 in the future.
JSF (or Jakarta Faces) 3.0 will be 1:1 the same as JSF 2.3, just with the jakarta.* package names.

In 2.3-next, we did BIG BIG cleanup of our codebase and build.
Wee also removed the old JSF EL (javax.faces.el.*) and @ManagedBean (javax.faces.bean.*) implementations.
What does this mean? The API (javax.faces.el.*) and (javax.faces.bean.*) is still there but the implementation of it has been removed partially. @ManagedBean's are now registered as CDI beans, which means that a CDI runtime is a required dependency now.

The biggest clenaup was that we merged back the "shared" and "shared-public" modules to myfaces-impl, as the shared modules are no longer used by other active projects under the MyFaces umbrella.
We also introduced some real integration tests with Arquillian, to test parts of the container integration and AJAX client side. This makes around 1600 unittests!

OK.... Lets compare some numbers!

JAR size:

	Mojarra 2.3	MyFaces 2.3	MyFaces 2.3-next
API		1318 kb	1043 kb
IMPL	3495 kb (combined)	2712 kb	2384 kb
Dependencies		241 kb (beanutils) 141 kb (digester)
TOTAL	3495 kb	4412 kb	3427 kb

Performance:
NOTE: this is not a full benchmark, it's only a single case to demonstrate the difference between MyFaces 2.3 and MyFaces 2.3-next, which was inspired from: https://www.oio.de/public/java/studie-jsf-mojarra-myfaces-performance-vergleich.htm
We have to rerun https://github.com/lu4242/performance-comparison-java-web-frameworks later for a real comparison between MyFaces and Mojarra.

	Mojarra 2.3	MyFaces 2.3	MyFaces 2.3-next
GET input.xhtml	Average: 67 ms	Average: 62 ms	Average: 43 ms
POST input.xhtml	Average: 115 ms	Average: 122 ms	Average: 108 ms
GET detail.xhtml	Average: 119 ms	Average: 124 ms	Average: 103 ms
POST detail.xhtml	Average: 70 ms	Average: 54 ms	Average: 43 ms
TOTAL	Average: 92 ms Throughput: 198.7/s	Average: 91 ms Throughput: 209.8/sec	Average: 74 ms Throughput: 264.2/sec

This means that MyFaces 3.0 is up to ~15% faster as the already very fast MyFaces 2.3 in this case.
We also did some memory finetuning - i just don't have any numbers right now.