Move view in metadata-modules/ and create atomic folder + module for each view entity (#14990)

# Introduction
Preparing view-filter and view-group introduction in v2 core engine
Moving view from `core-modules` to `metadata-modules`

## What happened

### Created dedicated modules for each view entity:
- ViewFieldModule
- ViewFilterModule
- ViewFilterGroupModule
- ViewGroupModule
- ViewSortModule

### Each module is now completely independent with its own:
- Controller
- Resolver
- Service
- Entity

### Created dedicated abstraction metadata module folder for:
- flat-view-field
- flat-view

### Dependencies 
- Eleminated circular dep on ViewModule to all others ones
- Granular import not importing the whole viewModule anymore everywhere


close https://github.com/twentyhq/core-team-issues/issues/1703

packages/twenty-server/src/engine/metadata-modules/view-group/entities/view-group.entity.ts

@@ -0,0 +1,73 @@
+import {
+  Column,
+  CreateDateColumn,
+  DeleteDateColumn,
+  Entity,
+  Index,
+  JoinColumn,
+  ManyToOne,
+  PrimaryGeneratedColumn,
+  Relation,
+  UpdateDateColumn,
+} from 'typeorm';
+
+import { SyncableEntity } from 'src/engine/workspace-manager/workspace-sync/interfaces/syncable-entity.interface';
+
+import { Workspace } from 'src/engine/core-modules/workspace/workspace.entity';
+import { FieldMetadataEntity } from 'src/engine/metadata-modules/field-metadata/field-metadata.entity';
+import { ViewEntity } from 'src/engine/metadata-modules/view/entities/view.entity';
+
+@Entity({ name: 'viewGroup', schema: 'core' })
+@Index('IDX_VIEW_GROUP_WORKSPACE_ID_VIEW_ID', ['workspaceId', 'viewId'])
+@Index('IDX_VIEW_GROUP_VIEW_ID', ['viewId'], {
+  where: '"deletedAt" IS NULL',
+})
+export class ViewGroupEntity extends SyncableEntity {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ nullable: false, type: 'uuid' })
+  fieldMetadataId: string;
+
+  @ManyToOne(() => FieldMetadataEntity, {
+    onDelete: 'CASCADE',
+  })
+  @JoinColumn({ name: 'fieldMetadataId' })
+  fieldMetadata: Relation<FieldMetadataEntity>;
+
+  @Column({ nullable: false, default: true })
+  isVisible: boolean;
+
+  @Column({ nullable: false, type: 'text' })
+  fieldValue: string;
+
+  @Column({ nullable: false, type: 'double precision', default: 0 })
+  position: number;
+
+  @Column({ nullable: false, type: 'uuid' })
+  viewId: string;
+
+  @Column({ nullable: false, type: 'uuid' })
+  workspaceId: string;
+
+  @CreateDateColumn({ type: 'timestamptz' })
+  createdAt: Date;
+
+  @UpdateDateColumn({ type: 'timestamptz' })
+  updatedAt: Date;
+
+  @DeleteDateColumn({ type: 'timestamptz' })
+  deletedAt?: Date | null;
+
+  @ManyToOne(() => Workspace, {
+    onDelete: 'CASCADE',
+  })
+  @JoinColumn({ name: 'workspaceId' })
+  workspace: Relation<Workspace>;
+
+  @ManyToOne(() => ViewEntity, (view) => view.viewGroups, {
+    onDelete: 'CASCADE',
+  })
+  @JoinColumn({ name: 'viewId' })
+  view: Relation<ViewEntity>;
+}