Remove workspace lints from templates (#4598)

This detaches the templates from monorepo's workspace lints, so the
lints for the templates can evolve separately as needed.

Currently the templates [re-use the monorepo's
lints](https://github.com/paritytech/polkadot-sdk-minimal-template/blob/bd8afe66ec566d61f36b0e3d731145741a9e9e19/Cargo.toml#L16-L43)
which looks weird.

cc @Kianenigma @gupnik