HciCaptures: Add CommandComplete

Add public methods to match or extract events in matchers.py.

Call the same private static methods to extract or match events.

- CommandComplete
- LeMetaEvent
- LeConnectionComplete

Test: cert/run --host
Bug: 145832107
Tag: #gd-refactor
Change-Id: I308e97cfe60dbcd351f211ff836c0516019412db