* [releases] add release notes for ink! 3.0-rc2

* [*] bump crate versions to ink! 3.0-rc2

* [releases] add missing ink! 3.0-rc2 release note

* [benches] fix lazy benchmarks

* [*] fix Cargo.toml documentation links

* [readme] show CI status of master branch always

* [readme] misc improvements

* [storage] make re-export of LazyHashMap inline

* [releases] add notes about ink_core split

* [allocator] add some crate level docs

* [storage] impl scale_info::TypeInfo for ink_storage::alloc::Box

* [metadata] improve docs slightly

* [storage] re-introduce StorageLayout impl for storage::Box

* [*] normalize authors for all ink! crates

* [lang, storage] add extern crate proc_macro

This is somehow needed for cargo publishing.

* [chores] add release notes for ink! 3.0

* [releases] 3.0: add note about trait definitions and implementations

* [*] bump all ink! crate versions to 3.0.0-rc1

* [releases] fix elipsis

* [releases] fix typo, improve sentences

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [releases] fix typo, improve sentences

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [releases] fix typo, improve sentences

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [releases] add note to lazy

* [releases] fix typo, improve sentences

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [releases] fix typo, improve sentences

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [releases] fix typo, improve sentences

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [releases] add missing release notes for ink! 2.1

* [releases] fix typo, improve sentences

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [releases] fix typo, improve sentences

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [releases] improve payable docs

* [*] update crate descriptions

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* [env] rename Env -> EnvBackend, TypedEnv -> TypedEnvBackend

* [env] rename EnvError -> Error

* [*] rename ink_env::EnvTypes -> Environment

Namely rename:
ink_env::EnvTypes -> Environment
ink_env::DefaultEnvTypes -> DefaultEnvironment

* [*] update cfg-if dependency 0.1 -> 1.0

* [alloc] rename ink_alloc -> ink_allocator

* [env] forgot to rename in lib.rs

* [env, lang] fix some bugs with ink_env::EnvError -> Error renaming

* [ci] adjust renaming of ink_alloc -> ink_allocator

* [env] apply rustfmt

* [lang/macro] re-enable disabled UI test

* [examples] DNS: apply rustfmt

* [examples] ERC-20, ERC-721: apply rustfmt