Templates are always taken from main

[abizjak]

Task description

cargo concordium init

always takes the templates from main. This is a bit problematic since we often have unreleased changes on main and it is awkward to make those without breaking something.

Instead of defaulting to main, we should specify a tag in cargo generate invocation.

We should support a special template/latest tag that we'd update each time we release new concordium-std, and this should be the default tag, and then we should also support normal release tags, e.g., concordium-std/7.1.0.

This would also make it simpler for us to develop.

[abizjak]

@DOBEN @limemloh Any thoughts?

[limemloh]

Seems like a reasonable approach, maybe even have template releases separate from concordium-std such that we can update these without updating concordium-std.

[rasmus-kirk]

Solved with #419 and this