feat: add basic structure of idp templates (#5053)

add basic structure and implement first providers for IDP templates to be able to manage and use them in the future

internal/idp/provider.go

@@ -0,0 +1,34 @@
+package idp
+
+import (
+	"context"
+
+	"golang.org/x/text/language"
+)
+
+// Provider is the minimal implementation for a 3rd party authentication provider
+type Provider interface {
+	Name() string
+	BeginAuth(ctx context.Context, state string, params ...any) (Session, error)
+	IsLinkingAllowed() bool
+	IsCreationAllowed() bool
+	IsAutoCreation() bool
+	IsAutoUpdate() bool
+}
+
+// User contains the information of a federated user.
+type User interface {
+	GetID() string
+	GetFirstName() string
+	GetLastName() string
+	GetDisplayName() string
+	GetNickname() string
+	GetPreferredUsername() string
+	GetEmail() string
+	IsEmailVerified() bool
+	GetPhone() string
+	IsPhoneVerified() bool
+	GetPreferredLanguage() language.Tag
+	GetAvatarURL() string
+	GetProfile() string
+}