feat: add configurable sender name and allow users to choose between system and personal SMTP accounts when sending emails

paperless-backend/src/database/entities/user-settings.entity.ts

@@ -23,6 +23,9 @@ export class UserSettings {
   @Column({ type: 'varchar', length: 255, nullable: true })
   SmtpFrom!: string | null;
 
+  @Column({ type: 'varchar', length: 255, nullable: true })
+  SmtpFromName!: string | null;
+
   @Column({ type: 'text', nullable: true })
   MailSignatureHtml!: string | null;
 }