Issue/CONFSERVER-54168 fix user list macro performance issue

The is to fix the performance issue and add a configurable limit to user list macro following the decision page here: https://bulldogwiki.internal.atlassian.com/wiki/display/CBF/Solution+for+CONFSERVER-54168+user+list+macro+performance+issue.

As for the default limit, I think 10,000 is reasonable. A rough performance test in my local environment shows the loading time (server side) as below: * 6000 users: ~5 seconds * 10000 users: ~ 8 seconds * 25000 users: ~ 20 seconds * 45000 users: ~ 33 seconds I think it is able to support 100,000 user entries as the result is pretty linear. Of course the browser will have a hard time to render the data.

BTW, the code style of the macro was terrible. I could not resist updating the style in the classes that I touched. I'm afraid it's already made code review a lot harder.

Branch status: https://server-syd-bamboo.internal.atlassian.com/browse/CBP-USERLISTERTRUNK2-4