Alcotezt-UX: rework on invocation headers I

Related to issue #5172 (closed)

Invocation headers

• Test files have traditionally contained a "test header", as described here: https://tezos.gitlab.io/developer/testing.html#conventions, including an invocation header.
• During the project, we've broken most of the invocation headers. Here's an example of a broken header: https://gitlab.com/tezos/tezos/blob/master/src/proto_016_PtMumbai/lib_client/test/test_client_proto_context.ml#L29

The current fix is to rewrite it as:

dune exec [TEST_FOLDER]/main.exe

• lib_base/test
• lib_clic/test
• lib_client_base/test
• lib_client_base_unix/test
• lib_context/test
• lib_crypto/test
• lib_crypto/test-unix
• lib_error_monad/test
• lib_mockup/test
• lib_protocol_environment/test_shell_context
• lib_protocol_environment/test
• lib_proxy/test
• lib_proxy/test-helpers/shell_services/test