Enable multi-platform development

[nickgerace]

TLDR: remove barriers to multi-platform development, like Bash and Make. Moreover, remove the nightly fmt dependency and improve testing to catch potential corner cases on multiple platforms.

Core:

• Rename "Reports" to "LabeledReports" since "Reports" is not of implied type Vec

Testing:

• Add second half to the integration test: comparing found reports with expected reports
  • Essentially, we run the core gfold loop again, but only generate reports and skip displaying them to stdout

CI:

• Removed nightly fmt check and job
• Moved fmt check to stable
• Update bors toml to match changes

Scripts:

• Convert scripts from Bash scripts to independent crates (multi-platform friendly)
• Add README to scripts directory
• Ensure script crates do not have their Cargo lockfile tracked in Git

Docs:

• Adding DEVELOPING file to replace Makefile
• Move THANKS and RELEASE files to new docs directory, along with DEVELOPING
• Replace make commands in README and RELEASE files

Misc:

• Remove Rust nightly dependency since it was solely for imports granulaity for rustfmt
  • This repository is once again only reliant on stable Rust toolchains
• Remove "rust-version" from Cargo toml since it was unused
• Remove Makefile entirely in favor of DEVELOPING file (multi-platform friendly)
• Update markdown code block languages as "shell" instead of "bash" to be multi-platform friendly

[nickgerace]

bors merge

[bors[bot]]

Build succeeded:

• Lint / Test / Build (ubuntu-latest)
• Test / Build (macos-latest)
• Test / Build (windows-latest)