lib: restructure to make space for database APIs

lib/_data_ingestion/jmdict/objects.dart

@@ -1,4 +1,4 @@
-import 'package:jadb/objects.dart';
+import 'package:jadb/_data_ingestion/sql_writable.dart';
 
 
 abstract class TableNames {

lib/_data_ingestion/kanjidic/objects.dart

@@ -1,4 +1,4 @@
-import 'package:jadb/objects.dart';
+import 'package:jadb/_data_ingestion/sql_writable.dart';
 
 abstract class TableNames {
   static const String character = 'KANJIDIC_Character';

lib/models/jmdict/word_search_result.dart

@@ -0,0 +1,3 @@
+class WordSearchResult {
+  // TODO: implement me
+}

lib/models/kanjidic/kanji_search_result.dart

@@ -0,0 +1,3 @@
+class KanjiSearchResult {
+  // TODO: implement me
+}

lib/models/radkfile/radicals_search_result.dart

@@ -0,0 +1,3 @@
+class RadicalsSearchResult {
+  // TODO: implement me
+}

lib/search.dart

@@ -0,0 +1,15 @@
+import 'package:jadb/models/jmdict/word_search_result.dart';
+import 'package:jadb/models/kanjidic/kanji_search_result.dart';
+import 'package:jadb/models/radkfile/radicals_search_result.dart';
+
+Future<KanjiSearchResult> searchKanji(String kanji) async {
+  throw UnimplementedError();
+}
+
+Future<RadicalsSearchResult> searchKanjiByRadicals(List<String> radicals) {
+  throw UnimplementedError();
+}
+
+Future<WordSearchResult> searchWord(String word) async {
+  throw UnimplementedError();
+}