Update routing and UI for performance checkout

Changed route paths and parameters for performance checkout to use '/performance/:performanceId/checkout' instead of '/selection/performance/:id'. Updated related components to use new route and param names. Improved UI spacing and styling in several components for better layout and consistency.

src/app/theater-layout/theater-layout.component.html

@@ -3,12 +3,12 @@
     Leinwand
   </p>
 </div>
-<div>
+<div class="mb-5">
   @for (row of seatsPerRow(); track $index) {
     <div class="flex items-center justify-between">
 
       <!-- Speaker -->
-      <div class="shrink-0 pl-25">
+      <div class="shrink-0 pl-20">
         @if ($index % 4 === 0) {
           <mat-icon class="material-symbols-outlined opacity-25" style="font-size: 30px; width: 30px; height: 30px">
             speaker
@@ -25,7 +25,7 @@
       <app-seat-row class="flex justify-center" [rowSeatList]="row"></app-seat-row>
 
       <!-- Speaker -->
-      <div class="shrink-0 pr-25">
+      <div class="shrink-0 pr-20">
         @if ($index % 4 === 0) {
           <mat-icon class="material-symbols-outlined opacity-25 mirrored" style="font-size: 30px; width: 30px; height: 30px">
             speaker