Use String instead of InputStream on importing templates
Replace parameter type from InputStream to String in
interfaces for MrrtReportTemplateService.importMrrtReportTemplate
MrrtReportTemplateValidator.validate and MrrtReportTemplateFileParser.parse
since template files are expected to be < 120kB and this greatly
simplifies handling as InputStreams can only be read once.
* change import, parse, validate iface to String instead of InputStream
* simplify tests by extracting repetivite things (getFile,
getFileContent) for test mrrt template files into helper methods
* improve RadiologyDashboardReportTemplatesTabControllerTest verify
service calls and use springs MockMultipartFile
* improve javadoc im MrrtReportTemplateService and tests
* merge tests of MrrtReportTemplateService.importMrrtReportTemplate
ensuring creation in db and filesystem into one test
* make sure that the InputStream's we open are closed via
try-with-resource syntax
* use apache commons FileUtils.writeStringToFile to write template to
file instead of OpenmrsUtils
