Add option to operate with NavEntry in the 'navigate' 'replace' edit-backstack

[vkatz]

EG:

val t = SomeScreen.toNavEntry(freeArgs=1)
navController.navigate(t)

[vkatz]

Pros - easy to navigate to NavEntry
Cons - some one can try smth like nc.navigate(nc.currentNavEntry) ...

Need to add some fool-protection...
Simple solution - add flag attached to NavEntry... make attached after being displayed in any nc, throw errot if some one tryes to navigate with attached entry

[vkatz]

soulution 2 create a separeta class eg: PendingNavEntry and allow to use it in navigation
Sounds more protective (even tho you can try to create new PendingNavEntry from existing entry - you will not be able to broke anything, it will be just new instance of entry)

[vkatz]

solution 3 - whenewer some one tryes to navigate/ add to backstack with NavEntry - create a copy (dest + args) and use it
<- wining for now