feat(tofu): Add support for deploying via OpenTofu

[abergmeier]

Description
Very simple initial config by introducing a new Deployment tofu. Simply uses an initialized Workspace to apply.

Since this needs an extension to 4beta11 schema introduces a new version 4beta12.

User facing changes
Has new tofu deploy struct with an obligatory workspace parameter.

Also introduces an integration test to ensure this works.

[oprudkyi]

@abergmeier thank you for effort,
I haven't checked deeply
but it seems pkg/skaffold/tofu/version_test.go expects version 0.16

			commands:        testutil.CmdRunOut("tofu version --json", `{"terraform_version": "0.16.0-alpha2"}`),
			expectedVersion: "0.16.0-alpha2",
		},

but there is already opentofu 1.8.6
https://github.com/opentofu/opentofu/releases

[abergmeier]

@abergmeier thank you for effort, I haven't checked deeply but it seems pkg/skaffold/tofu/version_test.go expects version 0.16

			commands:        testutil.CmdRunOut("tofu version --json", `{"terraform_version": "0.16.0-alpha2"}`),
			expectedVersion: "0.16.0-alpha2",
		},

but there is already opentofu 1.8.6 https://github.com/opentofu/opentofu/releases

Is there any reason why you think testing for a particular version is necessary?
My reasoning was that the test should be fine with handling an "obscure" case.
The code so far does not really care about which tofu version is installed.