Generate extended contract metadata (#62)

* Generate main.rs with quote for passing extension metadata

* Update template to scale-info 0.3

* Rename ink_abi package to ink_metadata

* Temporarily change ink dependency branch to aj-extra-metadata

* Fix up metadata generation codegen

* Promote metadata mod to directory

* Move InkProjectExtension data structure over from ink! PR

* Revert "Generate main.rs with quote for passing extension metadata"

This reverts commit 0929ce8a

* Make it compile

* Flatten metadata struct

* Fmt

* Capture ink metadata from stdout

* Update comment

* Construct hardcoded metadata values

* Remove contract metadata builder, it is redundant

* Generate contract wasm hash

* Refactor: extract CrateMetadata for use in both metadata and build

* Fmt

* Rust version

* Contract version

* Add remaining optional enhanced metadata

* Move wasm build, make repo and license work

* Just use a String for the license

* Remove unused variants

* Read docs and homepage urls directly from manifest

* Read user defined metadata

* Fmt

* This PR no longer depends on an updated version of ink!

* Fix test error, refactor commands to use common method name

* Fmt

* Refactor crate metadata collection

* Remove ink_lang dependency from generated metadata crate

* Fmt

* Return metadata path from generation

* Fmt

* Test metadata wasm hash

* Fmt

* Read ink language version

* Ensure tmp dir is cleaned up after build

* Make cargo-contract tmp dir not hidden

* Fmt

* Test source compiler, contract name, contract version

* Use ink branch temporarily

* Test for authors and documentation

* Test user provided metadata section

* Drop automatically handles tempdir removal

* Remove redundant unwind bound

* Comment crate features

* Revert template to point at ink master

* Self

* Update comment

* Remove redundant comment