feat: add schema user create and remove (#8494)

# Which Problems Are Solved

Added functionality that user with a userschema can be created and
removed.

# How the Problems Are Solved

Added logic and moved APIs so that everything is API v3 conform.

# Additional Changes

- move of user and userschema API to resources folder
- changed testing and parameters
- some renaming

# Additional Context

closes #7308

---------

Co-authored-by: Elio Bischof <elio@zitadel.com>

internal/repository/user/schemauser/aggregate.go

@@ -0,0 +1,25 @@
+package schemauser
+
+import (
+	"github.com/zitadel/zitadel/internal/eventstore"
+)
+
+const (
+	AggregateType    = "user"
+	AggregateVersion = "v3"
+)
+
+type Aggregate struct {
+	eventstore.Aggregate
+}
+
+func NewAggregate(id, resourceOwner string) *Aggregate {
+	return &Aggregate{
+		Aggregate: eventstore.Aggregate{
+			Type:          AggregateType,
+			Version:       AggregateVersion,
+			ID:            id,
+			ResourceOwner: resourceOwner,
+		},
+	}
+}