Add class script wrapper

[MaciejG604]

This should avoid deadlocks when threads are run from the static initalizer of wrapper object.

Closes #532 and #1933

The key to this issue is what's visible in the thread dump from this comment

ZScheduler-Worker-1" #15 daemon prio=5 os_prio=0 cpu=109,44ms elapsed=32,71s tid=0x00007f62544c7290 nid=0x22344 in Object.wait()  [0x00007f6214706000]
   java.lang.Thread.State: RUNNABLE
	at issue$minus7301$minusexample$minusko$Photos$$anon$1$$Lambda$481/0x0000000800e2c798.apply(Unknown Source)
	- waiting on the Class initialization monitor for issue$minus7301$minusexample$minusko$
	at zio.ZIO.map$$anonfun$1(ZIO.scala:927)
	at zio.ZIO$$Lambda$87/0x0000000800d3f3e0.apply(Unknown Source)

The background thread worker is waiting for object class to be initialized, but the object class initialization process is waiting for the background thread to finish, this introduces a deadlock.

As stated by David Crosson in #532 encapsulating the wait/join/Await.ready method into a additonal object fixed this in some cases by making the background thread not dependent on the initialization of the outer wrapper object introduced by Scala CLI.

[tgodzik]

Looks like some tests might need fixing up?

[lwronski]

LGTM

[Gedochao]

LGTM, commented on some nitpicks