refactor dbFormat (#19746)

* refactor dbFormat

* add simple tests

tests/stdlib/tdb.nim

@@ -0,0 +1,25 @@
+discard """
+  action: "compile"
+"""
+
+
+import db_mysql, db_odbc, db_postgres
+import os
+from stdtest/specialpaths import buildDir
+
+
+block:
+  block:
+    const dbName = buildDir / "db.sqlite3"
+    var db = db_mysql.open(dbName, "", "", "")
+    discard tryInsertId(db, sql"INSERT INTO myTestTbl (name,i,f) VALUES (?,?,?)", "t")
+
+  block:
+    const dbName = buildDir / "db.odbc"
+    var db = db_odbc.open(dbName, "", "", "")
+    discard tryInsertId(db, sql"INSERT INTO myTestTbl (name,i,f) VALUES (?,?,?)", "t")
+
+  block:
+    const dbName = buildDir / "db.postgres"
+    var db = db_postgres.open(dbName, "", "", "")
+    discard tryInsertId(db, sql"INSERT INTO myTestTbl (name,i,f) VALUES (?,?,?)", "t")

tests/stdlib/tdb.nims

@@ -0,0 +1 @@
+--styleCheck:off