feat: add MConn/FUSION cross-compile toolchains

[bambam955]

Description

We need to add the cross-compilation toolchains into the Docker images.

For now we will just install the MConn/FUSION toolchains for Buildroot and Yocto.

Proposal

• Update builder image to download and extract the toolchains from their Google Drive locations
  • Make sure that the Drive file IDs are passed via GHA secrets to keep locations private
  • Use gdown tool to get around the antivirus check failures (uv tool install gdown)
• Directory structure in builder:
  • /opt/cross-compile/buildroot-mconn-fusion for the Buildroot Qt 5.9.1 toolchain
  • /opt/cross-compile/yocto-mconn for the Yocto Qt 5.12.9 toolchain
• Update mconn and fusion images to copy these toolchains from builder
  • mconn should have both toolchains
  • fusion should just have Buildroot toolchain

[bambam955]

The Buildroot toolchain is in the Drive folder already. The Yocto toolchain is located in Q:/IT/Software/Qt and still needs copied over.