Feature: Adding recipe templates to print recipes.

Feautre: Recipe export to xlsx
Chore: Python 11 style type annotations
Chore: Moved to sqlalchemy 2.0
Chore: Minimum python is 3.11
Fix: Fix nullability of a lot of fields in the database.

overlord/src/app/purchase/purchase-resolver.service.ts

@@ -1,5 +1,5 @@
 import { Injectable } from '@angular/core';
-import { ActivatedRouteSnapshot, Resolve } from '@angular/router';
+import { ActivatedRouteSnapshot } from '@angular/router';
 import { Observable } from 'rxjs/internal/Observable';
 
 import { Voucher } from '../core/voucher';
@@ -8,7 +8,7 @@ import { VoucherService } from '../core/voucher.service';
 @Injectable({
   providedIn: 'root',
 })
-export class PurchaseResolver implements Resolve<Voucher> {
+export class PurchaseResolver {
   constructor(private ser: VoucherService) {}
 
   resolve(route: ActivatedRouteSnapshot): Observable<Voucher> {