Don't send workspace/configuration to clients that don't support it

https://github.com/redhat-developer/yaml-language-server/blob/3a74bdc22a1ae8a752e89cbf32616eacae163cea/src/languageserver/handlers/settingsHandlers.ts#L41

This function call (AFAICT) sends workspace/configuration, but it is called in response to workspace/didChangeConfiguration: https://github.com/redhat-developer/yaml-language-server/blob/3a74bdc22a1ae8a752e89cbf32616eacae163cea/src/languageserver/handlers/settingsHandlers.ts#L34. But that event should already give you the whole configuration!

Worse, the workspace/configuration request is sent to clients that don't support it. For example, I know that ALE (a Vim LSP client) prefers to use the workspace/didChangeConfiguration notification and does not support workspace/configuration, which it indicates by initializing with workspace.configuration capability false.

Essentially, this breaks using yaml-language-server with (for example) custom schema configuration because that configuration is never seen by the server.

I don't know if this could be a bug in the vscode-languageserver Node library, but it seems that sending workspace/configuration in response to the workspace/didChangeConfiguration notification is an anti-pattern.

Start in src/languageserver/handlers/settingsHandlers.ts around lines 34 and 41, then inspect how the server handles workspace/didChangeConfiguration and the client's workspace.configuration capability. Reproduce the custom schema configuration case with a client such as ALE; done means unsupported clients are not sent workspace/configuration and their configuration is still seen by the server.