Update URL after branch checkout

Issue: [Bug] Update URL after checkout branch (#110)

Description

Currently, the Web IDE URL still contains the old branch after successful branch checkout. This MR aims to solve that by introducing:

• A new field handleUpdateUrl in the client only config.
• The above is called by a new VSCode Mediator Command update-web-ide-url event, which is called when RELOAD_WITH_ID command is executed.

Note that this case does not apply to Example App and remote, which is currently being removed.

Demo

	Checkout branch no changes	Checkout branch with changes	Commit and checkout new branch
Before	checkout-branch-before.mov	checkout-branch-changes-before.mov	commit-checkout-before.mov
After	checkout-branch.mov	checkout-branch-changes.mov	commit-and-checkout-branch.mov