Add scalafix and organize-imports rule

.scalafix.conf

@@ -0,0 +1,13 @@
+rules = [
+      ProcedureSyntax
+      OrganizeImports
+]
+OrganizeImports {
+  coalesceToWildcardImportThreshold = 3
+  expandRelative = true
+  groupedImports = Keep
+  importsOrder = Ascii
+  groups = ["re:javax?\\.", "scala.", "re:(cats|fs2)\\.", "docspell.", "*"]
+  importSelectorsOrder = Ascii
+  removeUnused = true
+}