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/sessions/sessions.module.ts

@@ -1,11 +1,8 @@
 import { Module } from "@nestjs/common";
-import { CryptoModule } from "../crypto/crypto.module";
-import { DatabaseModule } from "../database/database.module";
 import { SessionsRepository } from "./repositories/sessions.repository";
 import { SessionsService } from "./sessions.service";
 
 @Module({
-	imports: [DatabaseModule, CryptoModule],
 	providers: [SessionsService, SessionsRepository],
 	exports: [SessionsService, SessionsRepository],
 })