Tweak set up instructions

[github-actions]

Closes #103

[yiendos]

hmm docker compose commands, when we have:
https://github.com/joomlatools/joomlatools-server/blob/master/bin/jtctl

Establish how to provide profile arguments into this command and remove references to docker compose

[yiendos]

sh bin/jtctl start

Actually loads up all available profiles:
https://github.com/joomlatools/joomlatools-server/blob/master/bin/jtctl#L183

So this issue/ Pull request is not needed

[yiendos]

@johanjanssens turned out to be pretty simple in the end, the jtctl start command takes care of launching the composer profiles automatically, my bad. I did notice that in the README we make no mention of jtctl so I've amended.