Implemented single scan station get +e errors

ref #67

src/errors/ScanStationErrors.ts

@@ -0,0 +1,25 @@
+import { IsString } from 'class-validator';
+import { NotAcceptableError, NotFoundError } from 'routing-controllers';
+
+/**
+ * Error to throw, when a non-existant scan station get's loaded.
+ */
+export class ScanStationNotFoundError extends NotFoundError {
+	@IsString()
+	name = "ScanStationNotFoundError"
+
+	@IsString()
+	message = "The scan station you provided couldn't be located in the system. \n Please check your request."
+}
+
+/**
+ * Error to throw when two scan stations' ids don't match.
+ * Usually occurs when a user tries to change a scan station's id.
+ */
+export class ScanStationIdsNotMatchingError extends NotAcceptableError {
+	@IsString()
+	name = "ScanStationIdsNotMatchingError"
+
+	@IsString()
+	message = "The ids don't match! \n And if you wanted to change a scan station's id: This isn't allowed!"
+}