chore: create TFC/TFE workspace using the Terraform CLI

[mutahhir]

Since we're moving to using TF CLI for Terraform Cloud, this PR removes the additional API call we make to TFC/TFE to create a workspace. Instead, it relies on the first cdktf diff or cdktf deploy by the developer to create a workspace on TFC.

The reason for this change is that by default workspaces created by the TFC API are set to use 'local execution', but when using the TF CLI and the CloudBackend, the created workspace uses 'remote execution'.

Other Improvements:

• The CLI checks the user's selected organisation if the selected workspace name already exists, and if so, allows the user to select a new name.
• Adding a tfe-hostname to the init command (Maybe I missed something, but I didn't see how TFE customers could use CDKTF before without going from local to remote?)
• Updating templates to respect tfe-hostname when generating the CloudBackend on init

Notes on Testing

I've only tested the PR on the latest release of TFE, however, it seems like the version that supports CloudBackend on TFE bundles with TF version 1.1.3 which is behind our new TF version support, so it should be safe to use.

[ansgarm]

[github-actions]

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