chore: Fix some vp create and vp migrate issues.

[cpojer]

This PR:

• Fixes wrong folder creation behavior when running something like vp create https://github.com/nkzw-tech/fate-template. It now uses the name of the template instead of creating https:/github.com/nkzw-tech/fate-template as a folder.
• Warns and asks the user to pick a new folder name when the folder already exists.
• Adds a progress spinner to vp create and vp migrate.
• Cleans up the vp migrate output to align with vp create and list manual migration steps at the end:

[netlify]

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[graphite-app]

Merge activity

• Mar 10, 2:04 AM UTC: This pull request can not be added to the Graphite merge queue. Please try rebasing and resubmitting to merge when ready.
• Mar 10, 2:04 AM UTC: Graphite disabled "merge when ready" on this PR due to: a merge conflict with the target branch; resolve the conflict and try again..
• Mar 10, 5:14 AM UTC: Graphite rebased this pull request as part of a merge.
• Mar 10, 5:20 AM UTC: Graphite rebased this pull request as part of a merge.
• Mar 10, 5:32 AM UTC: Graphite rebased this pull request as part of a merge.
• Mar 10, 5:44 AM UTC: @cpojer merged this pull request with Graphite.