Add supporting development resources (PR/issue templates, documentation site, packaging/release)

[0xalpharush]

To facilitate feedback from users, encourage upstream contributions, and make developers lives' easy there are a couple of things that may be helpful:

• PR template
• issue template
• documentation site
• Enabling the "Discussions" feature on Github
• CI integration i.e. github action
• Packaging/ installation. It would best if there's a one-liner way to install all dependencies including slither/ crytic-compile on Windows/Mac/Linux. Additionally, it would be great to make it easy to run "nightly" versions of Medusa should a user require a bug fix that has yet to be released

[Xenomega]

Updated the title here and removed CODEOWNERS as a TODO so it doesn't get bundled up as we also had #64.