[kbss-cvut/record-manager-ui#184] Implement detached import

I.e. import that is fully implemented by external service. In this case database is modified by separate service.

src/main/java/cz/cvut/kbss/study/rest/PatientRecordController.java

@@ -179,8 +179,10 @@ public RecordImportResult importRecordsJson(@RequestPart("file") MultipartFile f
     }
 
     @PostMapping(value = "/import/excel", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
-    public RecordImportResult importRecordsExcel(@RequestPart("file") MultipartFile file,
-                                            @RequestParam(name = "phase", required = false) String phase) {
+    public RecordImportResult importRecordsExcel(
+        @RequestPart("file") MultipartFile file,
+        @RequestParam(name = "phase", required = false) String phase,
+        @RequestParam(name = "detached", required = false, defaultValue = "true") boolean detached) {
 
         List<PatientRecord> records;
 
@@ -200,6 +202,22 @@ public RecordImportResult importRecordsExcel(@RequestPart("file") MultipartFile
 
         HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers);
 
+        if (detached) { // Implement variant where import is handled fully by external service
+            ResponseEntity<byte[]> responseEntity = restTemplate.postForEntity(
+                URI.create(excelImportServiceUrl),
+                requestEntity,
+                byte[].class
+            );
+
+            LOG.info("Import finished with status {}", responseEntity.getStatusCode());
+            if (responseEntity.getStatusCode() == HttpStatus.OK) {
+                byte[] responseBody = responseEntity.getBody();
+                LOG.debug("Response body length is {}", responseBody.length);
+            }
+
+            return new RecordImportResult();
+        }
+
         ResponseEntity<List<PatientRecord>> responseEntity = restTemplate.exchange(
                 URI.create(excelImportServiceUrl),
                 HttpMethod.POST,