[WIP] Synchronize SDK templates to separate repositories

[rzadp]

Aiming to satisfy:

• [EngAut] Automate Sync/Release the polakdot-sdk templates paritytech/eng-automation#6
• [Templates] Systematic way to synchronize the templates in this repo and substrate-developer-hub paritytech/polkadot-sdk#3155

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In this PR

• Focusing on minimal template for starters.
• Change the template to NOT use frame directly.
  • (because it is not published to crates and cannot be used outside of the monorepo)
  • (unless it is published under a different name?)
• Add a workflow to synchronize the templates.
  • push-based for now, eventually it will be based on releases/stable branches.
  • Yanks the template out of the workspace.
  • Polkadot SDK Version Manager came in handy.
  • Pushes the result to a separate repository.

Not yet done

• PR on build failure so it can be inspected.
• Parachain and solochain templates.
• Reading release version from the release or branch. (hardcoded 1.8.0 for now)

Current result

Current result can be reviewed here.

[rzadp]

Changed to 1.9.0