feat: add gRPC client utils helpers

[zepatrik]

Related issue(s)

closes #554

Extended commit message

Behold! The Keto gRPC client library now has useful helpers that allow you to replace:

- deltas := make([]*acl.RelationTupleDelta, len(tuples))
- for i := range rts {
- 	deltas[i] = &acl.RelationTupleDelta{
- 		Action:        acl.RelationTupleDelta_INSERT,
- 		RelationTuple: rts[i],
- 	}
- }
+ deltas := acl.RelationTupleToDeltas(tuples, acl.RelationTupleDelta_INSERT)

and

- &acl.Subject{Ref: &acl.Subject_Set{Set: &acl.SubjectSet{
- 	Namespace: "directories",
- 	Object:    "/photos",
- 	Relation:  "access",
- }}}
+ acl.NewSubjectSet("directories", "/photos", "access")

and

- &acl.Subject{Ref: &acl.Subject_Id{
- 	Id: "user1",
- }}
+ acl.NewSubjectID("user1")

Enjoy these new treats 🍫 🍭 🍦

[rauerhans]

It appears these helper methods are not yet published, even though they appear in the official documentation.
This is the latest version you can import github.com/ory/keto/proto/ory/keto/acl/v1alpha1, yet these helpers appear only in the latest github.com/ory/keto/proto/ory/keto/acl/v1alpha2.
This https://www.ory.sh/docs/keto/sdk/go example does already use those.
It's in another package tho:
"github.com/ory/keto/proto/ory/keto/relation_tuples/v1alpha2"

[zepatrik]

github.com/ory/keto/proto/ory/keto/acl/v1alpha2

is the correct version, please use that one. You can also use github.com/ory/keto/proto/ory/keto/acl/v1alpha1 before d29d42c

[rauerhans]

ah okay, so the example from the docs is a tad out of date already, the rest of the reference seems to be already documenting that rts api:
https://www.ory.sh/docs/keto/reference/proto-api
and this seems like a more up to date example:
https://github.com/ory/keto/blob/6c0e1ba87f4d3a355cebd0ea77f28319be2dd606/contrib/docs-code-samples/expand-api-display-access/00-create-tuples/main.go