client: move tests for example plugins in separate directory

Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
client: tests: add entries in Makefile for plugins

Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
client: move tests for freenetconfd plugin in separate directory

Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
client: tests: add entries in Makefile for core freenetconfd modules

Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
client: tests: move filer tests to new directory

Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>