feat: Update documentation, workflows and provider

[tmeckel]

• Bumped versions of Go and pulumictl in .devcontainer/Dockerfile
• Added examples and changed layout to package in docs/_index.md
• Corrected link to to Go documentation and clarified wording how to manually download provider in docs/installation-configuration.md
• fix: corrected exclude **/schema.go in .gitignore
• Removed obsolete usage of PreConfigureCallback and using an automatic mapping from resources, datasources to packages in provider/resources.go
• Added version check for Go version to Makefile
• Updated sdk/go.sum
• Added pull request GitHub workflow .github/workflows/pull-request.yml
• Updated .github/workflows/release.yml

Closes: #30
Closes: #29