ARTEMIS-1661 Support splitting of broker.xml

[michaelandrepearce]

Support XML standard XInclude thus allowing splitting of the broker.xml
Added test cases with split out config using include.

[michaelandrepearce]

just rebased.

[gaohoward]

@michaelandrepearce do you think we should add some documentation for this feature?

[adirubin]

Hi michaelandrepearce, thanks!
If I'm not mistaken, the server won't monitor the x-included files for changes, which could be a problem.

[michaelandrepearce]

@adirubin thats correct, you'll need to "touch" the broker.xml file to make the broker reload, this is very similar to the support for config modularity used in other projects such as log4j e.g. there also you need to "touch" the parent log4j.xml still to make log4j reload it.

It would be possible to make the file watcher watch x-included files also, but i want to introduce the basics first which is the simple support of breakout of files, via XML standards

[michaelandrepearce]

@gaohoward Updated docs 👍

[gaohoward]

@adirubin good point. I'm going to merge this and improve it in a separate commit.

[michaelandrepearce]

@gaohoward you on IRC? want to sync up / chat to avoid duplicating effort.