docs(readme): fix badges and remove CI section (#38)

* docs(readme): remove CI non-interactive mode section

Nobody initializes a repo from CI - the init command is for
maintainers setting up rnr in their project.

* docs(readme): use static badges for private repo

shields.io cannot access GitHub API for private repos, so using
static badges with for-the-badge style that link to the workflows.

* docs(readme): use GitHub native badges for workflow status

GitHub native badges show actual status and work for private repos.
shields.io cannot access GitHub API for private repos.

* docs(readme): restore shields.io dynamic badges with for-the-badge style

Author: CalvinAllen

README.md

@@ -78,13 +78,6 @@ Which platforms should this project support?
   Selected: 1.95 MB total
 ```
 
-Or use non-interactive mode for CI:
-```bash
-./rnr init --platforms linux-amd64,macos-arm64,windows-amd64
-./rnr init --all-platforms
-./rnr init --current-platform-only
-```
-
 ### What Gets Created
 
 ```