Draft: base-files: Move iopsys_version related functionality into iopsys-fwbank.sh
- Move iopsys version getters and cache management to iopsys-fwbank.sh
- Generalize cache management to the whole tree and call it from set_status...
brcm63xx platform adapting is needed in a separate MR
This makes for a more self-contained fwbank implementation, which does not leak into iopsys.sh