feat: Feature flag for relational tables (#10599)

# Which Problems Are Solved

This PR introduces a new feature flag `EnableRelationalTables` that will
be used in following implementations to decide whether Zitadel should
use the relational model or the event sourcing one.

# TODO

  - [x] Implement flag at system level
- [x] Display the flag on console:
https://github.com/zitadel/zitadel/pull/10615

# How the Problems Are Solved

  - Implement loading the flag from config
- Add persistence of the flag through gRPC endpoint
(SetInstanceFeatures)
- Implement reading of the flag through gRPC endpoint
(GetInstanceFeatures)

# Additional Changes

Some minor refactoring to remove un-needed generics annotations

# Additional Context

- Closes #10574

---------

Co-authored-by: Silvan <[email protected]>

console/src/assets/i18n/zh.json

@@ -1657,7 +1657,9 @@
       "CONSOLEUSEV2USERAPI_DESCRIPTION": "启用此标志时，控制台使用V2用户API创建新用户。使用V2 API，新创建的用户将以无初始状态开始。",
       "LOGINV2": "登录 V2",
       "LOGINV2_DESCRIPTION": "启用此选项将激活基于 TypeScript 的新登录界面，具有更高的安全性、性能和可定制性。",
-      "LOGINV2_BASEURI": "基础 URI"
+      "LOGINV2_BASEURI": "基础 URI",
+      "ENABLERELATIONALTABLES": "关系表",
+      "ENABLERELATIONALTABLES_DESCRIPTION": "启用此功能以使用关系表而不是投影来存储数据。目前此切换没有任何作用。"
     },
     "DIALOG": {
       "RESET": {