Replace rtt-log crate

[t-moe]

Sourcebox via Matrix:

I've seen embedded-test uses my rtt-log crate. While I appreciate this, I'm not sure if it's really a good idea in the long-term because of possible version conflicts with rtt-target. Because my crate as well as embedded-test has it as dependency, the version must match. The functionality of rtt-log is very little and there was some discussion long ago to directly include logging into rtt-target. Someone just has to do it.

Also: rtt-log does not allow to logging in blocking rtt mode (only discard on overflow)

[sourcebox]

If it's desired to have logging in a separate crate, I could also transfer ownership of rtt-log to the probe-rs organisation. That way, it would be easier to keep the versions in sync and add new features.

[t-moe]

Ok, so rtt-target 0.6.1 has been released.

Furthermore, the next embedded-test version will no longer depend on rtt-target or rtt-log, instead the users are encouraged to use something like #[embedded_test::tests(setup=rtt_target::rtt_init_log!())] if they want to setup logging early.