Package hosting options

https://github.com/eeue56/derw/blob/6f94fd8d2ed0bd8796b797dac2b14b09334d623b/src/cli/install.ts#L157-L171 (also, are you sure you don't want `console.error` instead of `log` here?)

Before this project digs itself into the same hole Elm did, please do not require that all packages come from Microsoft-owned GitHub. There are several valid reasons this is problematic from requiring agrees to GitHub's ToS to even begin participating in the community, to supporting FOSS platforms, avoiding vendor lock-in, promoting diversity, freedom+self-hosting, etc.

Suggestions:

1. require the full `git:` URL regardless of where the Git forge is hosted
2. above, but provide prefix shorthands for common ones like [Nixpkgs `fetch*`](https://github.com/NixOS/nixpkgs/tree/master/pkgs/build-support); which includes but not limited to GitHub, GitLab, Gitea, Sourcehut, Bitbucket, Savannah (e.g. `sourcehut:toastal/derw-lib`) (missing Codeberg though (but Codeberg is Gitea)). This allows self-hosting while adding convenience -- and once the tarball situation is figured out (I believe the latest blog entry is wrong about GitHub lacking tarballs (see [`fetchGitHub`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/fetchgithub/default.nix#L35))) all of these platform, including cgit support tarballs via git archive which can be used along the same shorthand switch/case.

Not acceptable:

1. Only GitHub
2. Giving GitHub special-er treament than say GitLab (e.g. **no** to `toastal/derw-lib` assuming GitHub since it's neither a full Git URL nor contains a shorthand as mentioned above in Suggestion#2, and more pedantically users must _always_ use `github:toastal/derw-lib`). GitHub does not need additional promotion or implicit endorsement.

Possible longer-term but likely way out of scope for contemporary version control:

1. Go beyond Git. SVN still exists as does Mercurial, Pijul, darcs, etc.