Update 'rosa' tool install/upgrade logic to account for new release assets

[tnierman]

The rosa CLI has updated it's release structure by providing a single checksum file and distributing tar archive files rather than raw executables. These changes allow backplane-tools to upgrade/install rosa given these alterations

[openshift-ci[bot]]

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[samanthajayasinghe]

/lgtm

[eth1030]

Resolves OSD-23956