README adjustments for new continuous integration

- Simplified the opening paragraph and combined it with the Get Started section. Removed unnecessary GitHub issues link.

- Updated the Releases and Roadmap section to reflect the new continuous integration structure.

- Removed Daily Builds section, as daily builds have been shut down. Daily builds are expected to be replaced with a simple snapshot link in the Download section.

- Removed API documentation links to decouple the website structure from the README file.