RISC-V support

[tresf]

I wanted to start discussion about adding RISC-V support, specifically riscv64 support.

Toolchains

At time of writing this, riscv64 is supported as a native OS install for Debian "sid" (unstable) and Ubuntu 23.10.

More helpful, probably, is the availability of a cross-compiler toolchain. There's some options:

• Debian: https://wiki.debian.org/RISC-V#Pre-built_toolchains
• Ubuntu: https://packages.ubuntu.com/search?keywords=gcc-riscv64-linux-gnu
• Docker: https://github.com/drujensen/riscv-ubuntu
• Clang/LLVM: https://stackoverflow.com/a/68583104/3196753

Tasks:

• Create and document initial linux_riscv64/libjssc.so binary
  • Add RISC-V support #144
• Add riscv64 support to native-lib-loader https://github.com/scijava/native-lib-loader
  • Add support for linux_riscv32, linux_riscv64 scijava/native-lib-loader#48
• Automate builds using CI/Actions
• Test in Qemu
• Test on physical hardware