refactor: use struct types for claim related types (#283)

* oidc: add regression tests for token claim json

this helps to verify that the same JSON is produced,
after these types are refactored.

* refactor: use struct types for claim related types

BREAKING CHANGE:
The following types are changed from interface to struct type:

- AccessTokenClaims
- IDTokenClaims
- IntrospectionResponse
- UserInfo and related types.

The following methods of OPStorage now take a pointer to a struct type,
instead of an interface:

- SetUserinfoFromScopes
- SetUserinfoFromToken
- SetIntrospectionFromToken

The following functions are now generic, so that type-safe extension
of Claims is now possible:

- op.VerifyIDTokenHint
- op.VerifyAccessToken
- rp.VerifyTokens
- rp.VerifyIDToken

- Changed UserInfoAddress to pointer in UserInfo and
IntrospectionResponse.
This was needed to make omitempty work correctly.
- Copy or merge maps in IntrospectionResponse and SetUserInfo

* op: add example for VerifyAccessToken

* fix: rp: wrong assignment in WithIssuedAtMaxAge

WithIssuedAtMaxAge assigned its value to v.maxAge, which was wrong.
This change fixes that by assiging the duration to v.maxAgeIAT.

* rp: add VerifyTokens example

* oidc: add standard references to:

- IDTokenClaims
- IntrospectionResponse
- UserInfo

* only count coverage for `./pkg/...`

pkg/client/rp/verifier_tokens_example_test.go

@@ -0,0 +1,86 @@
+package rp_test
+
+import (
+	"context"
+	"fmt"
+
+	tu "github.com/zitadel/oidc/v2/internal/testutil"
+	"github.com/zitadel/oidc/v2/pkg/client/rp"
+	"github.com/zitadel/oidc/v2/pkg/oidc"
+)
+
+// MyCustomClaims extends the TokenClaims base,
+// so it implmeents the oidc.Claims interface.
+// Instead of carrying a map, we add needed fields// to the struct for type safe access.
+type MyCustomClaims struct {
+	oidc.TokenClaims
+	NotBefore       oidc.Time `json:"nbf,omitempty"`
+	AccessTokenHash string    `json:"at_hash,omitempty"`
+	Foo             string    `json:"foo,omitempty"`
+	Bar             *Nested   `json:"bar,omitempty"`
+}
+
+// GetAccessTokenHash is required to implement
+// the oidc.IDClaims interface.
+func (c *MyCustomClaims) GetAccessTokenHash() string {
+	return c.AccessTokenHash
+}
+
+// Nested struct types are also possible.
+type Nested struct {
+	Count int      `json:"count,omitempty"`
+	Tags  []string `json:"tags,omitempty"`
+}
+
+/*
+idToken carries the following claims. foo and bar are custom claims
+
+	{
+		"acr": "something",
+		"amr": [
+			"foo",
+			"bar"
+		],
+		"at_hash": "2dzbm_vIxy-7eRtqUIGPPw",
+		"aud": [
+			"unit",
+			"test",
+			"555666"
+		],
+		"auth_time": 1678100961,
+		"azp": "555666",
+		"bar": {
+			"count": 22,
+			"tags": [
+				"some",
+				"tags"
+			]
+		},
+		"client_id": "555666",
+		"exp": 4802238682,
+		"foo": "Hello, World!",
+		"iat": 1678101021,
+		"iss": "local.com",
+		"jti": "9876",
+		"nbf": 1678101021,
+		"nonce": "12345",
+		"sub": "tim@local.com"
+	}
+*/
+const idToken = `eyJhbGciOiJSUzI1NiIsImtpZCI6IjEifQ.eyJhY3IiOiJzb21ldGhpbmciLCJhbXIiOlsiZm9vIiwiYmFyIl0sImF0X2hhc2giOiIyZHpibV92SXh5LTdlUnRxVUlHUFB3IiwiYXVkIjpbInVuaXQiLCJ0ZXN0IiwiNTU1NjY2Il0sImF1dGhfdGltZSI6MTY3ODEwMDk2MSwiYXpwIjoiNTU1NjY2IiwiYmFyIjp7ImNvdW50IjoyMiwidGFncyI6WyJzb21lIiwidGFncyJdfSwiY2xpZW50X2lkIjoiNTU1NjY2IiwiZXhwIjo0ODAyMjM4NjgyLCJmb28iOiJIZWxsbywgV29ybGQhIiwiaWF0IjoxNjc4MTAxMDIxLCJpc3MiOiJsb2NhbC5jb20iLCJqdGkiOiI5ODc2IiwibmJmIjoxNjc4MTAxMDIxLCJub25jZSI6IjEyMzQ1Iiwic3ViIjoidGltQGxvY2FsLmNvbSJ9.t3GXSfVNNwiW1Suv9_84v0sdn2_-RWHVxhphhRozDXnsO7SDNOlGnEioemXABESxSzMclM7gB7mYy5Qah2ZUNx7eP5t2njoxEYfavgHwx7UJZ2NCg8NDPQyr-hlxelEcfdXK-I0oTd-FRDvF4rqPkD9Us52IpnplChCxnHFgh4wKwPqZZjv2IXVCtn0ilKW3hff1rMOYKEuLRcN2YP0gkyuqyHvcf2dMmjod0t4sLOTJ82rsCbMBC5CLpqv3nIC9HOGITkt1Kd-Am0n1LrdZvWwTo6RFe8AnzF0gpqjcB5Wg4Qeh58DIjZOz4f_8wnmJ_gCqyRh5vfSW4XHdbum0Tw`
+const accessToken = `eyJhbGciOiJSUzI1NiIsImtpZCI6IjEifQ.eyJhdWQiOlsidW5pdCIsInRlc3QiXSwiYmFyIjp7ImNvdW50IjoyMiwidGFncyI6WyJzb21lIiwidGFncyJdfSwiZXhwIjo0ODAyMjM4NjgyLCJmb28iOiJIZWxsbywgV29ybGQhIiwiaWF0IjoxNjc4MTAxMDIxLCJpc3MiOiJsb2NhbC5jb20iLCJqdGkiOiI5ODc2IiwibmJmIjoxNjc4MTAxMDIxLCJzdWIiOiJ0aW1AbG9jYWwuY29tIn0.Zrz3LWSRjCMJZUMaI5dUbW4vGdSmEeJQ3ouhaX0bcW9rdFFLgBI4K2FWJhNivq8JDmCGSxwLu3mI680GWmDaEoAx1M5sCO9lqfIZHGZh-lfAXk27e6FPLlkTDBq8Bx4o4DJ9Fw0hRJGjUTjnYv5cq1vo2-UqldasL6CwTbkzNC_4oQFfRtuodC4Ql7dZ1HRv5LXuYx7KPkOssLZtV9cwtJp5nFzKjcf2zEE_tlbjcpynMwypornRUp1EhCWKRUGkJhJeiP71ECY5pQhShfjBu9Nc5wDpSnZmnk2S4YsPrRK3QkE-iEkas8BfsOCrGoErHjEJexAIDjasGO5PFLWfCA`
+
+func ExampleVerifyTokens_customClaims() {
+	v := rp.NewIDTokenVerifier("local.com", "555666", tu.KeySet{},
+		rp.WithNonce(func(ctx context.Context) string { return "12345" }),
+	)
+
+	// VerifyAccessToken can be called with the *MyCustomClaims.
+	claims, err := rp.VerifyTokens[*MyCustomClaims](context.TODO(), accessToken, idToken, v)
+	if err != nil {
+		panic(err)
+	}
+	// Here we have typesafe access to the custom claims
+	fmt.Println(claims.Foo, claims.Bar.Count, claims.Bar.Tags)
+	// Output: Hello, World! 22 [some tags]
+}