Improve performance on metadata computation (#12785)

In this PR:

## Improve recompute metadata cache performance. We are aiming for
~100ms

Deleting relationMetadata table and FKs pointing on it
Fetching indexMetadata and indexFieldMetadata in a separate query as
typeorm is suboptimizing

## Remove caching lock

As recomputing the metadata cache is lighter, we try to stop preventing
multiple concurrent computations. This also simplifies interfaces

## Introduce self recovery mecanisms to recompute cache automatically if
corrupted

Aka getFreshObjectMetadataMaps

## custom object resolver performance improvement:  1sec to 200ms

Double check queries and indexes used while creating a custom object
Remove the queries to db to use the cached objectMetadataMap

## reduce objectMetadataMaps to 500kb
<img width="222" alt="image"
src="https://github.com/user-attachments/assets/2370dc80-49b6-4b63-8d5e-30c5ebdaa062"
/>

We used to stored 3 fieldMetadataMaps (byId, byName, byJoinColumnName).
While this is great for devXP, this is not great for performances.
Using the same mecanisme as for objectMetadataMap: we only keep byIdMap
and introduce two otherMaps to idByName, idByJoinColumnName to make the
bridge

## Add dataloader on IndexMetadata (aka indexMetadataList in the API)

## Improve field resolver performances too

## Deprecate ClientConfig

packages/twenty-server/src/engine/metadata-modules/data-source/data-source.entity.ts

@@ -1,11 +1,12 @@
 import {
   Column,
   CreateDateColumn,
+  DataSourceOptions,
   Entity,
+  Index,
+  OneToMany,
   PrimaryGeneratedColumn,
   UpdateDateColumn,
-  DataSourceOptions,
-  OneToMany,
 } from 'typeorm';
 
 import { ObjectMetadataEntity } from 'src/engine/metadata-modules/object-metadata/object-metadata.entity';
@@ -13,6 +14,7 @@ import { ObjectMetadataEntity } from 'src/engine/metadata-modules/object-metadat
 export type DataSourceType = DataSourceOptions['type'];
 
 @Entity('dataSource')
+@Index('IDX_DATA_SOURCE_WORKSPACE_ID_CREATED_AT', ['workspaceId', 'createdAt'])
 export class DataSourceEntity {
   @PrimaryGeneratedColumn('uuid')
   id: string;