Update the configuration documentation and change the maven plugin artifactID
Update the configuration documentation and change the maven plugin artifactID

This commit is to update the global configuration model document to align
with the changes in #1226, move maven plugin inside extensions.

thusithathilina/carbon-kernel,jsdjayanga/carbon-kernel,daneshk/carbon-kernel,wso2/carbon-kernel,jsdjayanga/carbon-kernel,jsdjayanga/carbon-kernel,wso2/carbon-kernel,thusithathilina/carbon-kernel,laki88/carbon-kernel,ChanakaCooray/carbon-kernel,daneshk/carbon-kernel,cnapagoda/carbon4-kernel,nuwandi-kernel/carbon-kernel,cnapagoda/carbon4-kernel,laki88/carbon-kernel,cnapagoda/carbon4-kernel,wso2/carbon-kernel,daneshk/carbon-kernel,thusithathilina/carbon-kernel,nuwandi-kernel/carbon-kernel,nuwandi-kernel/carbon-kernel,laki88/carbon-kernel,ChanakaCooray/carbon-kernel,ChanakaCooray/carbon-kernel