Shared object file for Raspberry Pi

## Currently

When I install the nodejs library with `node i vosk`, I get something like this in the `node_modules`

```
node_modules/vosk/lib/
|-- linux-x86_64/libvosk.so
|-- osx-universal/libvosk.so
|-- win-x86_64/libvosk.dll
```

But Raspberry Pi is ARM64, not x64_64, which results in...

## Related issue

...[this open issue](https://github.com/alphacep/vosk-api/issues/1356) has many people describing the same problem occurring on other systems. Someone even mentioned my workaround.

This issue is created as a solution proposal instead of a bug report.

## Kindly requesting

Could you please add `linux-aarch64/libvosk.so`? I am assuming that somewhere in the depths there is also an `if` statement that decides which `.so` file to use. It should be updated to use `linux-aarch64` when on ARM64 arch.

## Current workaround

To fix this, one has to download the proper release manually and replace the `node_modules/vosk/lib/linux-x86_64/libvosk.so` with it.

```sh
wget https://github.com/alphacep/vosk-api/releases/download/v0.3.45/vosk-linux-aarch64-0.3.45.zip
unzip vosk-linux-aarch64-0.3.45.zip
cd vosk-linux-*/ # the folder you just unzipped
mv libvosk.so node_modules/vosk/lib/linux-x86_64/libvosk.so
```

## Post scriptum

I am not familiar with the codebase, but if you tell me which configs to change, I can probably do this myself. I don't mind spending some time adding support for other architectures. Evidently, you already produce releases for these other architectures already.