feat(server): custom library scanning interval (#4390)

* add automatic library scan config options

* add validation

* open api

* use CronJob instead of cron-validator

* fix tests

* catch potential error of the library scan initialization

* better description for input field

* move library scan job initialization to server app service

* fix tests

* add comments to all parameters of cronjob contructor

* make scan a child of a more general library object

* open api

* chore: cleanup

* move cronjob handling to job repoistory

* web: select for common cron expressions

* fix open api

* fix tests

* put scanning settings in nested accordion

* fix system config validation

* refactor, tests

---------

Co-authored-by: Jason Rasmussen <jrasm91@gmail.com>

server/src/domain/system-config/system-config.core.ts

@@ -13,6 +13,7 @@ import {
   VideoCodec,
 } from '@app/infra/entities';
 import { BadRequestException, ForbiddenException, Injectable, Logger } from '@nestjs/common';
+import { CronExpression } from '@nestjs/schedule';
 import { plainToInstance } from 'class-transformer';
 import { validate } from 'class-validator';
 import * as _ from 'lodash';
@@ -120,6 +121,12 @@ export const defaults = Object.freeze<SystemConfig>({
   theme: {
     customCss: '',
   },
+  library: {
+    scan: {
+      enabled: true,
+      cronExpression: CronExpression.EVERY_DAY_AT_MIDNIGHT,
+    },
+  },
 });
 
 export enum FeatureFlag {