Support linux_gcc_arm64 arch in 6.7.0

[rectalogic]

Initial support, probably missing some cases. Fixes #750

Some interactive testing:

$ aqt list-qt linux desktop
5.9.0 5.9.1 5.9.2 5.9.3 5.9.4 5.9.5 5.9.6 5.9.7 5.9.8 5.9.9
5.10.0 5.10.1
5.11.0 5.11.1 5.11.2 5.11.3
5.12.0 5.12.1 5.12.2 5.12.3 5.12.4 5.12.5 5.12.6 5.12.7 5.12.8 5.12.9 5.12.10 5.12.11 5.12.12
5.13.0 5.13.1 5.13.2
5.14.0 5.14.1 5.14.2
5.15.0 5.15.1 5.15.2
6.0.0 6.0.1 6.0.2 6.0.3 6.0.4
6.1.0 6.1.1 6.1.2 6.1.3
6.2.0 6.2.1 6.2.2 6.2.3 6.2.4
6.3.0 6.3.1 6.3.2
6.4.0 6.4.1 6.4.2 6.4.3
6.5.0 6.5.1 6.5.2 6.5.3
6.6.0 6.6.1 6.6.2
6.7.0 6.7.0

$ aqt list-qt linux desktop --arch 6.7.0
linux_gcc_64 linux_gcc_arm64

$ aqt list-qt linux desktop --arch 6.6.0
gcc_64 wasm_singlethread wasm_multithread

$ aqt install-qt linux desktop 6.7.0 linux_gcc_arm64 --outputdir /tmp/Qt
[...]
INFO    : Finished installation of qtsvg-Linux-Debian_11_6-GCC-Linux-Debian_11_6-AARCH64.7z in 1.31891796
INFO    : Finished installation of qttools-Linux-Debian_11_6-GCC-Linux-Debian_11_6-AARCH64.7z in 1.71985637
INFO    : Downloading qttranslations...
[...]


$ aqt install-qt linux desktop 6.7.0 linux_gcc_64 --outputdir /tmp/Qt
[...]
INFO    : Finished installation of qtsvg-Linux-RHEL_8_8-GCC-Linux-RHEL_8_8-X86_64.7z in 2.46250538
INFO    : Downloading qttranslations...
[...]

$ aqt install-qt linux desktop 6.6.0 gcc_64 --outputdir /tmp/Qt
[...]
INFO    : Finished installation of qtsvg-Linux-RHEL_8_6-GCC-Linux-RHEL_8_6-X86_64.7z in 2.44938992
INFO    : Downloading qttranslations...
[...]

$ aqt install-qt linux desktop 6.6.0 --outputdir /tmp/Qt
[...]
INFO    : Finished installation of qtsvg-Linux-RHEL_8_6-GCC-Linux-RHEL_8_6-X86_64.7z in 3.00820996
INFO    : Downloading qttranslations...
[...]

$ aqt install-qt linux desktop 6.7.0 --outputdir /tmp/Qt
[...]
INFO    : Finished installation of qtsvg-Linux-RHEL_8_8-GCC-Linux-RHEL_8_8-X86_64.7z in 2.25437083
INFO    : Downloading qttranslations...
[...]