Re-introduce technical experience panel interview

Created by: jeanduplessis

Also specifies the list of teammates to choose from for scheduling panel interviews. This allows us to remove it from the interviews repo: https://github.com/sourcegraph/interviews/pull/165

Why

1. After taking part in a recent candidate's technical experience interview I've come to the conclusion that there is much value to be gained from this interview in helping understand whether a candidate is suitable to join Sourcegraph.
2. While I tried to incorporate the signal checks in the hiring manager interview, it simply does not allow enough time to go into the level of detail required to get confidence in someone's technical experience.
3. This interview is also very valuable in helping evaluate the seniority of a candidate