Support arm64 for core and plugins

[scothis]

Describe the feature request

ARM CPUs are increasing in popularity for servers and desktop use, especially with the introduction of Apple Silicon. The Tanzu CLI not supporting this popular architecture creates unnecessary friction for users of newer Macs.

Describe alternative(s) you've considered

The Tanzu CLI can run under rosetta, but locally compiled plugins are built for the native host architecture by default darwin_arm64, the tanzu plugin install command insists on installing darwin_amd64 binaries which are not built so the install fails.

Compiling the Tanzu CLI directly for darwin_arm64 also works, but installing pre-built plugins will fail unless they are compiled for darwin_arm64, which they are not.

Additional context

Macs are a bit special in that they can execute either darwin_arm64 (native) or darwin_amd64 (emulated). When installing a plugin for a darwin_arm64 if the plugin is not available as darwin_arm64, it should automatically fall back to darwin_amd64.

Previously vmware-tanzu/tanzu-framework#440

[marckhouzam]

The support for Darwin ARM64 has been released with v1.1.0.
I will keep this open as we are working on the same support for Windows ARM64 now that Windows 11 has out-of-the-box emulation for AMD64