Improve Rust support

[jjohannes]

• Custom additions from here should eventually move into these plugin. (Clarify with @anthony-swirldslabs before starting.)
• Rethink if the tools setup can be improved.
  • What is need in addition to what we already have (related Rust: automatically install LLVM for 'clang-cl' and 'llvm-lib' used in Windows cross-compilation #97)?
  • Can the tools be installed differently to not be "out of date" so often. Maybe use a solution like this: Public API for DependencyManagementServices and FileSystemAccess (use case: tool installation) gradle/gradle#32225

[anthony-swirldslabs]

Re: https://github.com/hashgraph/hedera-cryptography/blob/main/cryptography/hedera-cryptography-rpm/build.gradle.kts

On one hand, we're implementing WRAPS 2.0 which will deprecate the whole hedera-cryptography-rpm thing, so that setup won't be needed.
On the other hand, generally, it feels less complicated to nuke zig as an extra dependency and just go with plain GNU tools because as this compressor build shows, they support the cross-compilation, although require a bit more tuning - but at the same time provide as with more options on how to tune them and are more compatible with external Rust libraries than zig is. However, this might be a bigger task overall.
All in all, I'd park this for now. In short term, we'll eventually nuke this particular Gradle script, and that could be good-enough for short-term.

As for improvements, I'd suggest:

1. To make sure the tools installation task is platform-dependent. I don't want to install tools for windows when I'm only building for Mac.
2. To make the build ONLY compile for the native host target by default. The cross-compilation should only be triggered via a separate task (and/or a special option) that would only be enabled in GitHub CI builds. Plain build/assemble shouldn't produce cross-platform binaries. Again, I don't want to waste my time building for Windows and Linux (or even darwin-x86) when I'm on darwin-aarch64.

[jjohannes]

With #404 #416 the local development experience is improved.

On Macos, you can now run ./gradlew assemble or ./gradlew qualityGate and it only installs the toolchain for the local machine and does not do cross-compilation.

Simplifying cross-compilation and possible removing Zig (?) in that context will be the next step. For more context and pointers, see: #404 (comment)