Add support for ISO file authenticity verification

[merillr]

Is your feature request related to a problem? Please describe.

When using the bigip_software_install module to install a new image, installation fails if the liveinstall.checksig database key is enabled and the .sig for the ISO is not pre-uploaded to /shared/images. See K15226.

Describe the solution you'd like

Provide a new module to upload .sig files or modify the bigip_software_image or bigip_software_install module to include this functionality.

Describe alternatives you've considered

I'm not sure that the ansible.builtin.copy module is an option because of the connection: local in the playbook and user accounts defaulting to tmsh. Disabling liveinstall.checksig prior to a bigip_software_install task is a workaround, but defeats the purpose.

Additional context

Resulting error is: failed (Signature file not found - /shared/images/BIGIP-<Version-Build>.iso.sig)