Support Multiple Workspace Folders for TypeScript/JavaScript

[maks-ivanov]

This pull request addresses issue #21 by enabling support for multiple workspace folders for TypeScript and JavaScript in the LSP manager. The changes include:

1. New LspClientKey Enum: Introduced a new enum LspClientKey to differentiate between clients per language and clients per workspace folder.
2. Client Management: Updated the Manager struct to manage LSP clients using the new key, allowing multiple TypeScript/JavaScript servers to run concurrently, one for each workspace folder.
3. Workspace Folder Detection: Implemented logic to detect and initialize LSP clients for each workspace folder found in the project.
4. Client Retrieval: Modified the get_client method to retrieve the appropriate client based on the workspace folder for TypeScript/JavaScript.

These changes ensure that the TypeScript/JavaScript language server can operate independently for each workspace folder, aligning with the requirements outlined in the issue.

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This pull request was co-created with Cosine Genie

Original Task: lsproxy/ps7dkfc535ze
Author: Maksim Ivanov