Add a solution for composing bracketed resources

[iravid]

Composing brackets is a pain:

val resource1: IO[E, R1]
val resource2: IO[E, R2]

resource1.bracket(release1) { r1 =>
  resource2.bracket(release2) { r2 =>
    // ...
  }
}

Prior art:

• http://hackage.haskell.org/package/managed - very simple to port, partially applies IO.bracket to create a monad
• http://hackage.haskell.org/package/resourcet - allows more fine-grained control on resource cleanup (e.g. cleanup handlers can run before the bracket region ends), abstracts over the effect type. Would be harder to port; I don't know if ZIO needs this data type built in.
• https://github.com/typelevel/cats-effect/blob/master/core/shared/src/main/scala/cats/effect/Resource.scala - abstracts over the effect type and uses a separate algebra to facilitate interpreters that need different resource scoping rules (e.g. streams). Also has a nice utility for easily lifting resources that are <: AutoCloseable.
• Add scala.util.Using, for automatic resource management scala/scala#6907 - hardcoded to Try

[neko-kai]

There's also Using in 2.13 standard library that does this for Try - scala/scala#6907

[iravid]

True. Added that and cats-effect's Resource