Create Narayana specific coding style instead of using not much restrictive WFLY one

It would be good to have a Narayana specific source code style which would be covering the perspective of the Narayana team on source code formatting.

Currently Narayana uses the checkstyle plugin with rules from WildFly project https://github.com/wildfly/wildfly-checkstyle-config/blob/master/src/main/resources/wildfly-checkstyle/checkstyle.xml

From some discussions in the team, e.g. https://github.com/jbosstm/narayana/pull/1783/files#r574560952, it's considered not covering all aspects of the well readable code.

The code should be formatted in consistent manner to be readable and easily comprehensible. It would be good to create Narayana specific ruleset which will be used for (new) Narayana projects - e.g. LRA.