Remove GetByBean method because sometimes it's danger when query condition parameter is zero and also introduce new generic methods (#28220)

The function `GetByBean` has an obvious defect that when the fields are
empty values, it will be ignored. Then users will get a wrong result
which is possibly used to make a security problem.

To avoid the possibility, this PR removed function `GetByBean` and all
references.
And some new generic functions have been introduced to be used.

The recommand usage like below.

```go
// if query an object according id
obj, err := db.GetByID[Object](ctx, id)
// query with other conditions
obj, err := db.Get[Object](ctx, builder.Eq{"a": a, "b":b})
```

services/repository/lfs_test.go

@@ -52,7 +52,7 @@ func storeObjectInRepo(t *testing.T, repositoryID int64, content *[]byte) string
 	pointer, err := lfs.GeneratePointer(bytes.NewReader(*content))
 	assert.NoError(t, err)
 
-	_, err = git_model.NewLFSMetaObject(db.DefaultContext, &git_model.LFSMetaObject{Pointer: pointer, RepositoryID: repositoryID})
+	_, err = git_model.NewLFSMetaObject(db.DefaultContext, repositoryID, pointer)
 	assert.NoError(t, err)
 	contentStore := lfs.NewContentStore()
 	exist, err := contentStore.Exists(pointer)