Add RISCV64 testing support and default to clean compiler output

[pbatard]

This branch adds two mostly unrelated patches.

The first one sets the compilation to produce output similar to the one generated with automake/libtools when enabling silent rules, namely something like:

make[1]: Entering directory '/home/runner/work/gnu-efi/gnu-efi/x86_64/apps'
  CC       t.o
  LD       t.so
  OBJCOPY  t.efi
  CC       t2.o
  LD       t2.so
  OBJCOPY  t2.efi
  CC       t3.o
  LD       t3.so
  OBJCOPY  t3.efi
  CC       t4.o
  LD       t4.so
  OBJCOPY  t4.efi
  (etc...)

This makes any warning or error much easier to locate as it'll instantly pop out. But of course, this is done at the expense of verbosity. Just as with the silent rules of automake however, the old verbose behaviour can be restored by adding V=1 when invoking make.

The second patch adds RISCV64 testing, using the unmodified RISCV_VIRT_CODE.fd firmware image from http://ftp.ie.debian.org/debian/pool/main/e/edk2/qemu-efi-riscv64_2024.02-2_all.deb (which again I am repackaging at https://efi.akeo.ie as the package link can and will be changed with new Debian releases).

Note that this requires running on Ubuntu 24.04 (rather than Ubuntu 22.04, which is what ubuntu-latest from GitHub Actions currently still maps to), as this will only work with QEMU 8.2 or later.

I also had a patch that added dr0.efi testing to our tests, but unfortunately, as long as #27 is not resolved, this cannot be added as the test will fail on RISCV64...