Metal: Support for more network bonding modes

**What I'd like:**

It would be great to add support for more bonding modes instead of only mode 1 / active-backup. Equinix Metal as an example uses mode 4 / 802.3ad / active-active with the following example configuration:

```
bond-downdelay 200
bond-miimon 100
bond-mode 4
bond-updelay 200
bond-xmit_hash_policy layer3+4
bond-lacp-rate 1
```

**Any alternatives you've considered:**

None since bottlerocket only supports mode 1 / active-backup for network bonding.

No files, tests, or entry points are named. Start by locating the current network-bonding implementation and configuration handling, then compare its mode 1 support with the mode 4 / 802.3ad example in the issue. Done means the requested bonding settings are supported and verified with appropriate tests or configuration validation.

Written by the indexing model from the issue text.