TRUNK-5080 Reorganize checkstyle
* remove webapp-checkstyle.xml since it only contained one rule which was applied to JSP files which have all been deleted.
* remove the webapp/pom.xml config for checkstyle since
webapp-checkstyle.xml is deleted
* rename/move the openmrs-checkstyle.xml to the root of the repository
as checkstyle.xml
* inline the openmrs-checkstyle.properties values into checkstyle.xml
since they are only used in this file. this way they can also be read
be cloud providers such as codacy and codeclimate
* adapt the root pom's checkstyle config to point to the new file
locations
* add a suppression rule to excempt test classes from checkstyle rule MethodNames since they contain undersores in the method names
* remove the checkstyle-license-header.txt since we are checking
license headers with the mycilla maven plugin already
