Support layer 2 MAC packets

### What problem does this feature solve or what does it enhance?

We currently don't handle layer 2 packets at all, despite them containing some very useful information (e.g. https://www.sharetechnote.com/html/Handbook_LTE_TimingAdvance.html).

### Proposed Solution

This kinda has two _layers_ of support:

1. Simply relay layer 2 packets into the PCAP so we can analyze them there
2. Write a parser for layer 2 packets so we can inspect them via analyzers

The former is much easier than the latter.

### Alternatives Considered

_No response_