configurePlugins command for tsserver

[minestarks]

Implements #18604

• Add a new tsserver command, configurePlugins.
• Add a new optional method to PluginModule, onConfigurationChanged. Plugin authors can implement this.
• When configurePlugins is invoked, it will pass on the configuration object to any loaded plugin instances with a matching name.
• This configuration is meant to override the initial configuration passed in in create/PluginCreateInfo as well as any previous configurations passed in in configurePlugins.
• The updated configuration will also be remembered by tsserver so that it can be passed in, in the create call, to any projects loaded in the future with the matching plugin. This is needed for consistency -- the caller of configurePlugins would have no way of knowing whether the plugin/project of interest has yet been loaded.

cc @mjbvz

[mjbvz]

API changes for server and plugins look good! Just let me know how you want us to expose this on the VS Code side

[minestarks]

@mjbvz Thanks! Just opened corresponding PR microsoft/vscode#61756 , let me know if that works.

[sheetalkamat]

Changes look good but we need test.

[zafarmandor786]

Thanks

[minestarks]

@sheetalkamat test added!

[sheetalkamat]

Build failed with api