In #1657 the initial prototype version of XCM was introduced. However, it was coded against the v0 parachains, which at the time of writing this was already eradicated.

Note that this issue doesn't require complete polishness of XCM. The goal of this issue is to land XCM on master adapting it to the parachains v1 code to ultimately achieving feature parity with the v0 version - i.e. launch rococo v1 with XCM and demonstrate the same functionality.