Surface Port Alias to SwitchInterface and Decide Naming Strategy

[hardikdr]

Summary

Expose a human-friendly alias for SwitchInterfaces (e.g., vendor port alias), and decide whether to use alias as the resource name or store it in status/labels.

Motivation

Interface names are often sparse or non-sequential (e.g., only even numbers), which makes iterating and operating on ports awkward. An alias would improve usability and reduce confusion when mapping physical ports to CRs.

[maxmoehl]

I'd prefer if we could have names that do not depend on the vendor of the device. One thing which always trips me is one- vs. zero-indexing. When communicating with the technicians they always talk about ports and breakouts. The ports are obviously one-indexed as they just count the ports on the back whereas SONiC starts with zero and just skips ports that are not broken out making it almost impossible to do the conversion reliably without explicitly looking it up each time. If there are breakouts, it's also important to know which breakout on which physical port is meant. Therefore my preferred scheme would be eth$port-$breakout. The conversion would then be (assuming four lanes per port):

• Ethernet0 -> eth1-1 (no breakout)
• Ethernet4 -> eth2-1 (broken out into two)
• Ethernet6 -> eth2-3
• Ethernet8 -> eth3-1 (broken out into four)
• Ethernet9 -> eth3-2
• Ethernet10 -> eth3-3
• Ethernet11 -> eth3-4

This naming could be used across all vendors with each operator implementing the conversion. The technical name used to manipulate the state would live somewhere inside the resource so that the reconciler doesn't have to constantly convert between the two.

_{Now imagine doing this conversion in your head, good look :)}

Edit: this rather belongs to #82, reposting over there.