This patch stops using `processLauncher` to launch web servers. Process
Launcher
will spawn a new process group which is separate from test runner.
This might result in unexpected behavior, e.g. `kill -sigkill
-<testrunnerpid>` will orphan web server process.
Instead, this patch simply spawns web server and sends `SIGTERM` to it
when ready.
This patch moves parts of docker configuration to a plugin so that
it can rely on repoter for stdout.
Drive-by: provide all plugins with reporter in the `setup` callback.
Fixes#8206.
Since #8206 is a long-awaited (~ 1 year old), popular (~ 45 reactions, frequently requested in community channels, etc.), this PR aims to unblock folks.
Notably, we do not innovate on the `webServer` API, despite knowing we're not in love with it. We'll save the innovation for either Plugins or a new `LaunchConfigs` option. (We haven't yet arrived at a Plugin API we like, and instead of launching a new option guessing what the "better" launchConfig API would be, let's wait and see how folks use this new Array-variant of `webServer` which—despite its name—can be used for non-Web Server launches!
