feat: one-line install script (#1924)

* feat: one-line install script

* remove homebrew support

* remove arch linux

* use proper filename for packages

* fix variable format

* fix systemd instructions

* fixes to standalone script

* fix missing var bugs

* fix standalone install

* fix for MacOS

* format

* fix armv7 assets and zips

* remove windows

* update install docs

* support external sources with shellcheck

* shfmt

* add external sources to GitHub action & unfold

* change wording

* first template docs

* default to /usr/local instead

* add option for binary name

.github/workflows/coder.yaml

@@ -52,6 +52,8 @@ jobs:
       - uses: actions/checkout@v3
       - name: Run ShellCheck
         uses: ludeeus/action-shellcheck@1.1.0
+        env:
+          SHELLCHECK_OPTS: --external-sources
         with:
           ignore: node_modules