Change clients to have a login bash as entrypoint

[maxnoe]

This makes it possible to directly run a command in the docker image like this:

docker run [...] -v rucio-clients rucio download test:test.dat

-l is necessary to have bash load the startup script in /etc/profile.d/ which sets up the rucio config.

Alternatively, that code could also be integrated into the entry point.

[maxnoe]

@bari12 @rcarpa could you have a look? I am happy to adapt if you want something differently

[maxnoe]

@maany That should be docker run, right? exec requires an existing container

Edit: sorry, I see what you mean, that also wasn't possible before.

[bari12]

Awesome, thanks a lot!