standalone cli (#89)

* standalone cli

* noop test

* some more plugins

* cleanup

* finish cli

* Fixes

* make it work

* more docs

* update labeler

Author: romainmenke

.github/ISSUE_TEMPLATE/css-issue.yml

@@ -32,7 +32,7 @@ body:
   - type: dropdown
     id: npx
     attributes:
-      label: Does it happen with `npx <plugin-name> minimal-example.css`?
+      label: Does it happen with `npx @csstools/csstools-cli <plugin-name> minimal-example.css`?
       multiple: false
       options:
         - "Yes"

.github/ISSUE_TEMPLATE/plugin-issue.yml

@@ -34,7 +34,7 @@ body:
   - type: dropdown
     id: npx
     attributes:
-      label: Can you reproduce it with `npx <plugin-name> minimal-example.css`?
+      label: Can you reproduce it with `npx @csstools/csstools-cli <plugin-name> minimal-example.css`?
       multiple: false
       options:
         - "Yes"