Better error handling when starting the SPL language server

[queeniema]

• If running in embedded mode and initialization takes longer than 1 minute, then show a notification to the user and ask them if they want to try switching to socket mode.
• If running in socket mode, one issue users may run into is 'port already in use' errors if they have multiple VS Code windows open. The workaround for this is to use different port values for the Server: Port setting in the workspace settings for each window. To help users recover, we can detect if a port is in use and if so, show a notification to offer to change the port either temporarily (for the current session) or permanently (for the workspace).

[queeniema]