Move email/ resources to mail/, added invoice generated email to admin, updated email template

app/Models/Account.php

@@ -253,13 +253,15 @@ class Account extends Model implements IDs
 
 	/* METHODS */
 
-	public function invoice_next(): Collection
+	public function invoice_next(Carbon $date=NULL): Collection
 	{
-		// Collect all the invoice items for our active services
-		$nextdate = ($x=$this
+		$svs = $this
 			->services_active
 			->filter(fn($item)=>$item->isBilled() && $item->invoice_next)
-			->sortBy(fn($item)=>(string)$item->invoice_next))
+			->sortBy(fn($item)=>(string)$item->invoice_next);
+
+		// Collect all the invoice items for our active services
+		$nextdate = $date ?: $svs
 			->first()
 			?->invoice_next
 			->clone();
@@ -271,7 +273,7 @@ class Account extends Model implements IDs
 			->subDay()
 			->endOfday();
 
-		$items = $x
+		$items = $svs
 			->filter(fn($item)=>$item->invoice_next->lessThan($nextitemsdate))
 			->sortBy(fn($item)=>$item->invoice_next.$item->name)
 			->map(fn($item)=>$item->next_invoice_items($nextitemsdate))