[Bug] consider rust-toolchain.yaml when building from other directory

[milyin]

Describe the bug

See fix #617
This fix makes ad-hoc update which fixes specific issue.
@yellowhatter commented that that the real cause of the problem is probably ignoring rust-toolchain.yaml when building from other directory. Need to be revised

To reproduce

System info

[yellowhatter]

I faced the same error on RMW and fixed it occasionally by making 1.75 toolchain default. This is a sign that rust-toolchain.yaml is definitely ignored.

The official doc is not clear about this, but people say that Cargo respects rust-toolchain.yaml only in CWD

[yellowhatter]

@milyin please talk to Martin Geoff ( @gmartin82 ) about this: ZettaScaleLabs@b84e333

[gmartin82]

Also see this PR which copies the toolchain config file into the build directory to ensure cargo picks it up.

[milyin]

Validated with https://crates.io/crates/version_check library that requested compiler version is used