Move Ensure and ExtensionsRoots to Platform.Assertions library?

[FreePhoenix888]

[konard]

We have to decide what is more important here:

• The fact that assert/ensure operation throws an exception.
• The role of action they do.

[konard]

Assertion (Ensure) is based on predicate (condition).
Throw is unconditional exception triggering.

[FreePhoenix888]

Assertion (Ensure) is based on predicate (condition). Throw is unconditional exception triggering.

Then we should move it to the Platform.Assertions