Provide extension point to declare a DAP server

[angelozerr]

Today DAP server is configured with DAP run configuration https://github.com/redhat-developer/lsp4ij/blob/main/docs/dap/UserGuide.md

The DAP run configuration parameters should cover all usecases but:

• the UI can looks like complex
• the server must be installed at hand (download som DAP server files, etc)
• it is not extendable (cannot consume custom DAP request, cannot customize icon, cannot customize inline values to get the proper position of DAPvalue, etc)

It would be nice to provide the capability to define a DAP server with extension point in an external IJ plugin. It will provide the capability

• to host the DAP server in the plugin
• cutomize the DAP server to consume custom DAP request, customize icons, customize inline value
• provide a simple UI for run configuration (specific to the DAP server)
• etc