Replace cost unit endpoints for staff member

• cost unit changes are made by patch staff
• so no separate cost unit endpoints anymore

apps/api/src/app/database/services/config.service.ts

 import { Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
-import { ConfigFullDto, EnumDefinitionDto } from '@lib/dto';
+import { ConfigFullDto, EmailConfigDto, EnumDefinitionDto } from '@lib/dto';
 import AppConfig from '../entities/config.entity';
 import { UsersService } from './users.service';
 
@@ -63,6 +63,31 @@ export class ConfigService {
     }
   }
 
+  async findEmail(): Promise<EmailConfigDto> {
+    const setting = await this.settingsRepository.findOne({ where: { key: 'email' } });
+    return setting ? setting.content as EmailConfigDto : <EmailConfigDto>{
+      sendPassword: '',
+      sendServer: '',
+      sendUsername: '',
+      textEdvEpilog: '',
+      textEdvProlog: ''
+    };
+  }
+
+  async patchEmail(emailDef: EmailConfigDto): Promise<void> {
+    const settingToUpdate = await this.settingsRepository.findOne({ where: { key: 'email' } });
+    if (settingToUpdate) {
+      settingToUpdate.content = emailDef;
+      await this.settingsRepository.save(settingToUpdate);
+    } else {
+      const newSetting = await this.settingsRepository.create({
+        key: 'email',
+        content: emailDef
+      });
+      await this.settingsRepository.save(newSetting);
+    }
+  }
+
   async findCitizenShips(): Promise<string[]> {
     const setting = await this.settingsRepository.findOne({ where: { key: 'citizenships' } });
     return setting ? setting.content as string[] : [];