refactor(db): change SQLite driver from github.com/jinzhu/gorm/dialects/sqlite to github.com/glebarez/go-sqlite (#1626)

* sqlite 驱动从 github.com/jinzhu/gorm/dialects/sqlite 改为 github.com/glebarez/go-sqlite，以移除对 cgo 的依赖

* // 兼容已有配置中的 "sqlite3" 配置项

* Update models/init.go: 修改变量名

models/folder_test.go

@@ -106,7 +106,7 @@ func TestFolder_GetChildFolder(t *testing.T) {
 }
 
 func TestGetRecursiveChildFolderSQLite(t *testing.T) {
-	conf.DatabaseConfig.Type = "sqlite3"
+	conf.DatabaseConfig.Type = "sqlite"
 	asserts := assert.New(t)
 
 	// 测试目录结构