Update readme

[mlasch]

Rework the readme file a bit.

• Remove layout section This section provides limited use since Github as well as modern IDEs have good file browsing built in. The source layout section consumes valuable visual space on the Github landing page and distracts from other important information.

• Move CI batch to the top There is no need for a separate section for batches. This nicely fits below the project name.

• Update cmake commands to build examples Update build commands for examples with cmake variables to configure the build process.

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[kwjones]

Thank you for requesting the update to the examples build process. I'd not worked with Wakaama for many months, and expected the previous cmake/make process to be the same (given the README.md). Surprise! Really nice work from all the contributors. I cannot thank you all enough. Having an "open" client alternative is extremely important. Again, many thanks!