BPE Throws NPE If BPMN File Defined in Process Plugin Not Found

[hhund]

The BPE should throw a use full error message if a BPMN file defined in a process plugins is not found. Currently a NPE is thrown at:

highmed-dsf/dsf-bpe/dsf-bpe-server/src/main/java/org/highmed/dsf/bpe/plugin/ProcessPluginDefinitionAndClassLoader.java

Line 178 in f372b75

String read = IOUtils.toString(in, StandardCharsets.UTF_8);