Update development documentation for the new project structure

[TamiTakamiya]

Problem

Previously ansible-language-server was provided as a separate repository. While it is now merged in to the vscode-ansible repository, the development documentation (development.md) is still assuming the old structure. The documentation needs to be updated for the new project structure.

Solution

Update the deveopment documentation to reflect the latest project structure.

Alternatives

If the development documentation is provided on another web site, it would be fine as well.

Additional context

No response