Windows & some quality-of-life improvements

[hdhoang]

Hi, this is a groundwork for #67, so that tests pass on windows. I will follow up with failure switching next.

Somehow my fork's cargo cache on mac is broken https://github.com/hdhoang/askalono/runs/3891311728?check_suite_focus=true#step:3:6. I hope this PR goes OK.

Description of changes:

• subprojects' lock files are updated automatically by any cargo invocation
• remove symlinks for datasets
• add rustup "+toolchain" syntax support for some just targets

For example:

just lint +stable
just lint +nightly

just all +stable t
just all +nightly c

However, cli and diag targets pass arguments to askalono-cli, and cause ambiguity with rustup/cargo positional arg. I cannot add this there.

And finally, I applied some clippy suggestions from both toolchains.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jpeddicord]

Thanks! I'll go ahead and merge this. Don't worry about the mac cache; if it's still broken I can help fix it up before pushing a new release.

[hdhoang]

Thanks! Would you mind adding label "hacktoberfest-accepted" for this PR?

[jpeddicord]

Done!