feat(v3alpha): write actions (#8225)

# Which Problems Are Solved

The current v3alpha actions APIs don't exactly adhere to the [new
resources API
design](https://zitadel.com/docs/apis/v3#standard-resources).

# How the Problems Are Solved

- **Breaking**: The current v3alpha actions APIs are removed. This is
breaking.
- **Resource Namespace**: New v3alpha actions APIs for targets and
executions are added under the namespace /resources.
- **Feature Flag**: New v3alpha actions APIs still have to be activated
using the actions feature flag
- **Reduced Executions Overhead**: Executions are managed similar to
settings according to the new API design: an empty list of targets
basically makes an execution a Noop. So a single method, SetExecution is
enough to cover all use cases. Noop executions are not returned in
future search requests.
- **Compatibility**: The executions created with previous v3alpha APIs
are still available to be managed with the new executions API.

# Additional Changes

- Removed integration tests which test executions but rely on readable
targets. They are added again with #8169

# Additional Context

Closes #8168

internal/api/grpc/server/middleware/execution_interceptor.go

@@ -14,6 +14,7 @@ import (
 	"github.com/zitadel/zitadel/internal/query"
 	exec_repo "github.com/zitadel/zitadel/internal/repository/execution"
 	"github.com/zitadel/zitadel/internal/telemetry/tracing"
+	"github.com/zitadel/zitadel/internal/zerrors"
 )
 
 func ExecutionHandler(queries *query.Queries) grpc.UnaryServerInterceptor {
@@ -143,6 +144,9 @@ func (c *ContextInfoRequest) GetHTTPRequestBody() []byte {
 }
 
 func (c *ContextInfoRequest) SetHTTPResponseBody(resp []byte) error {
+	if !json.Valid(resp) {
+		return zerrors.ThrowPreconditionFailed(nil, "ACTION-4m9s2", "Errors.Execution.ResponseIsNotValidJSON")
+	}
 	return json.Unmarshal(resp, c.Request)
 }