Support SystemBootOptions commands and add boot/lan helpers methods

[canteuni]

This pull request aims to add support for setting boot mode and boot device, and add some useful methods to abstract how to set VLAN ID, mac address, ip source and boot options without having to deal with bit manipulation.

• Add Get/Set SystemBootOptions request and response definitions in msgs/chassis.py
• Add helpers methods to easily manipulate lan parameters in lan.py
• Add helpers methods to easily manipulate boot options in chassis.py

I'm willing to contribute to this project so do not hesitate to tell me if I'm doing something wrong !

[hthiery]

Hi, thanks for this contribution. That looks good so far.

But some remarks:

• could you split the features into several commits, e.g. bootcmds and lan commands
• could you add some unit tests for the new features
• could you add a signed-off-by tag to the commits

Thanks

[canteuni]

Hi,

Thanks for the remarks, I'll work on that :+1:

[hthiery]

Thank you!