coin: Provision vcpkg on Ubuntu 24.04 aarch64

The three ubuntu-24.04-arm64 configurations in cmake_platforms.yaml and
cmake_platforms_static_release.yaml name arm64-linux-qt as their vcpkg
host and target triplet, but no such triplet existed and the template
did not provision vcpkg, so the variables had no effect.

arm64-linux-qt.cmake is the upstream arm64-linux triplet plus the
openssl customization x64-linux-qt.cmake carries, keeping openssl
dynamic with VCPKG_FIXUP_ELF_RPATH while everything else links
statically. The wrapper scripts mirror the Ubuntu 24.04 x86_64 ones and
differ only in the triplet passed to install-vcpkg-ports.sh.

The first provisioning round has to build openssl, protobuf and grpc
for the new triplet. Existing x86_64 cache entries are unaffected.

Task-number: QTBUG-115715
Pick-to: 6.12
Change-Id: I6f464dd65cd4031ca7856cf0049678568ea33d93
Reviewed-by: Elias Toivola <elias.toivola@qt.io>