wasmtime downloading support

[whyoleg]

The PR is draft because:

• dev version of wasmtime is used as nor v25 nor v26 supports GC
• EH proposal is not yet implemented and so those lines should be uncommented before running tasks
• test task will fail because of some internal issues in wasmtime (https://github.com/bytecodealliance/wasmtime/issues/5032#issuecomment-2483656302)
• tested on Mac only

Example of output:

> Task :wasmWasiWasmtimeRun
Hello from Kotlin via WASI
Current 'realtime' timestamp is: 1731949197746582000
Current 'monotonic' timestamp is: 1261833