refactor(modules): mark DatabaseModule and CryptoModule as global and remove redundant imports

Optimize module imports by marking `DatabaseModule` and `CryptoModule` as global. Remove explicit imports from other modules to reduce duplication and improve maintainability. Update environment variable limits for image and GIF sizes in production.

backend/src/contents/contents.module.ts

@@ -1,7 +1,5 @@
 import { Module } from "@nestjs/common";
 import { AuthModule } from "../auth/auth.module";
-import { CryptoModule } from "../crypto/crypto.module";
-import { DatabaseModule } from "../database/database.module";
 import { MediaModule } from "../media/media.module";
 import { S3Module } from "../s3/s3.module";
 import { ContentsController } from "./contents.controller";
@@ -9,7 +7,7 @@ import { ContentsService } from "./contents.service";
 import { ContentsRepository } from "./repositories/contents.repository";
 
 @Module({
-	imports: [DatabaseModule, S3Module, AuthModule, CryptoModule, MediaModule],
+	imports: [S3Module, AuthModule, MediaModule],
 	controllers: [ContentsController],
 	providers: [ContentsService, ContentsRepository],
 	exports: [ContentsRepository],