Add scale::Output to Wrap (no_std) + minor improvements (#381)

* [core] add scale::Output to Wrap (no_std) + minor improvements

* [core] turn asserts into debug_asserts

* [core] remove unused is_empty method
15 jobs for master in 7 minutes and 57 seconds (queued for 38 seconds)
Status Job ID Name Coverage
  Check
passed #478097
linux-docker
check-std

00:01:24

passed #478098
linux-docker
check-wasm

00:01:40

 
  Workspace
passed #478099
linux-docker
build-std

00:01:45

passed #478100
linux-docker
build-wasm

00:02:22

passed #478102
linux-docker
clippy-std

00:01:19

passed #478103
linux-docker
clippy-wasm

00:01:24

passed #478104
linux-docker
fmt

00:00:21

passed #478101
linux-docker
test

00:01:14

 
  Examples
passed #478107
linux-docker
examples-clippy-std

00:01:04

passed #478108
linux-docker
examples-clippy-wasm

00:01:01

passed #478109
linux-docker
examples-contract-build

00:01:13

passed #478106
linux-docker
examples-fmt

00:00:13

passed #478110
linux-docker
examples-generate-metadata

00:01:51

passed #478105
linux-docker
examples-test

00:01:28

 
  Publish
passed #478111
linux-docker
publish-docs

00:01:19