Move db related basic functions to models/db (#17075)

* Move db related basic functions to models/db

* Fix lint

* Fix lint

* Fix test

* Fix lint

* Fix lint

* revert unnecessary change

* Fix test

* Fix wrong replace string

* Use *Context

* Correct committer spelling and fix wrong replaced words

Co-authored-by: zeripath <art27@cantab.net>

models/gpg_key_test.go

@@ -8,6 +8,7 @@ import (
 	"testing"
 	"time"
 
+	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/modules/timeutil"
 
 	"github.com/stretchr/testify/assert"
@@ -192,9 +193,9 @@ Unknown GPG key with good email
 }
 
 func TestCheckGPGUserEmail(t *testing.T) {
-	assert.NoError(t, PrepareTestDatabase())
+	assert.NoError(t, db.PrepareTestDatabase())
 
-	_ = AssertExistsAndLoadBean(t, &User{ID: 1}).(*User)
+	_ = db.AssertExistsAndLoadBean(t, &User{ID: 1}).(*User)
 
 	testEmailWithUpperCaseLetters := `-----BEGIN PGP PUBLIC KEY BLOCK-----
 Version: GnuPG v1