This diff adds support for running OONIRun v1 links.
Run with `miniooni` using:
```
./miniooni -i LINK oonirun
```
Part of https://github.com/ooni/probe/issues/2184
This diff refactors the ./internal/cmd/miniooni pkg and moves the code
for running experiments inside of the ./internal/oonirun pkg.
It's the first concrete step towards https://github.com/ooni/probe/issues/2184.
