[JENKINS-18583] - Added propagation of Instance ID to the newInstance() method

Signed-off-by: Oleg Nenashev <nenashev@synopsys.com>
Another attempt to make newInstance() work properly.
textarea and textbox cannot have prefix, so approach won't work

Signed-off-by: Oleg Nenashev <nenashev@synopsys.com>
Merge branch 'multiple-scm-instatination-fix' of https://github.com/jenkinsci/perforce-plugin into multiple-scm-instatination-fix
Added initial implementation of Data classes

Signed-off-by: Oleg Nenashev <nenashev@synopsys.com>
Removed previous hacks with request handling

Signed-off-by: Oleg Nenashev <nenashev@synopsys.com>
Removed another obsolete method

Signed-off-by: Oleg Nenashev <nenashev@synopsys.com>