DELTASPIKE-786 improved documentation

 (steps for a release)
DELTASPIKE-789 ClientWindowConfig needs to extend Serializable
DELTASPIKE-790 cache result for JsfModuleConfig#isDelegatedWindowHandlingEnabled
DELTASPIKE-791 release notes for v1.2.0
DELTASPIKE-777 moved config to profile
DELTASPIKE-777 added plugin-version
Revert "DELTASPIKE-777 added plugin-version"

This reverts commit 311aef6b54715b6ac6141ed9dbe5e04abeda40aa.
Revert "DELTASPIKE-777 moved config to profile"

This reverts commit cd805aabc4191545ca84f8f0832efe7d193c77e1.
DELTASPIKE-792 - Fix javadoc generation for JDK < 8
DELTASPIKE-690: Addng reorganised and rewritten content
Feedback from gerhard
DELTASPIKE-690: Edited background section in overview.adoc
update pom.xml

Changed staging site path
DELTASPIKE-690: General text imporvements to 'Get Started' pages
DELTASPIKE-690: More edits to existing adoc