[DOC] Order the development home page (#657)

This an attempt to order page by topic to let contributors find information
more easily.

docs/development/README.md

@@ -3,11 +3,18 @@
 General information are available in the [Contributing Guide](../../CONTRIBUTING.md).
 Information about the library internals are available in the [architecture folder](./docs/architecture) or in html form in the [documentation site](https://process-analytics.github.io/bpmn-visualization-js/#_architecture_and_development)
 
-Here are some tips to help during development:
-- [how to support new BPMN elements](./bpmn-support-how-to.md)
-- [mxgraph version bump](./mxgraph-version-bump.md)
-- [IDE configuration](./ide-configuration.md)
+Here are some tips to help during development.
+
+## Build and develop
+
 - [how to build & code style](./development.md)
+- [IDE configuration](./ide-configuration.md)
+
+## Contributing
 - [testing](./testing.md)
+- [how to support new BPMN elements](./bpmn-support-how-to.md)
 - [how to submit us your work](./pull-request.md)
+- [mxgraph version bump](./mxgraph-version-bump.md)
+
+## Misc
 - [for the maintainers](./maintainers.md)