* nix shell config

* fix darwin

* update nightly for nix shell

Bump wasm-builder-runner

1.0 wasm-builder-runner is not compatible with 2.0 wasm-builder https://github.com/paritytech/substrate/pull/7283#issuecomment-705824314

Architecture specific toolchains are not allowed in this file.
We can assume that stable is the default toolchain and should not
dictate with which toolchain the user builds the client. Also this
breaks under macOS.

We are only interested with which toolchain the runtime is build.
For this we should set the WASM_BUILD_TOOLCHAIN variable.

Closes #95

* Add toolchain file

* Remove reference to script that uses latest nightly

* Remove link to nonexistent subheading

* Create Issue templates

- Report a Bug
- Suggest a Feature
- Ask a Question

paritytech/substrate#6557 (comment)

* Upgrade to v2.0.0-rc4

* Better updates to README

Co-authored-by: Joshy Orndorff <JoshOrndorff@users.noreply.github.com>

Co-authored-by: Joshy Orndorff <JoshOrndorff@users.noreply.github.com>

* Fixed typo

* Updated image organization