refactor: delete server code and refactor migration extension

[Alex-Sol]

Description

1. Replace LSP with node-powershell method;
2. Fix the concurrency situation;

3. Activate the extension when open or save.

   Checklist

• [ ] I have read the Submitting Changes section of CONTRIBUTING.md
• [ ] The title of the PR is clear and informative
• [ ] The appropriate ChangeLog.md file(s) has been updated:
  • For any service, the ChangeLog.md file can be found at src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md
  • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header -- no new version header should be added
• [ ] The PR does not introduce breaking changes
• [ ] If applicable, the changes made in the PR have proper test coverage
• [ ] For public API changes to cmdlets:
  • [ ] a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
    • {Please put the link here}
  • [ ] the markdown help files have been regenerated using the commands listed here

[Alex-Sol]

@isra-fel please review.