Multi src astar (#594)

## Description:
Samples border shore tiles and uses multi-a* for determining the
transport ship spawn cell.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:

<DISCORD USERNAME>
evan

---------

Co-authored-by: evan <openfrontio@gmail.com>

src/core/execution/ShellExecution.ts

@@ -19,7 +19,7 @@ export class ShellExecution implements Execution {
   ) {}
 
   init(mg: Game, ticks: number): void {
-    this.pathFinder = PathFinder.Mini(mg, 2000, true, 10);
+    this.pathFinder = PathFinder.Mini(mg, 2000, 10);
     this.mg = mg;
   }