Add a couple of buildkite agents, based off of the config we're using
for whitby (thanks!) for building my own projects that are closed
source.
Change-Id: I2c73538595002fdf4116f534dc9a5806f17e0558
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2044
Reviewed-by: glittershark <grfn@gws.fyi>
Tested-by: BuildkiteCI