Add option for blocking mode in console command

[eduardoweiland]

bin/resque checks for an environment variable BLOCKING to set working mode to blocking. But, different from other options (e.g. COUNT, INTERVAL), this one cannot be set with a command line argument when running bin/console resque:worker-start.

What do you think about adding this option to the command, something like --blocking or -b?

[PhilETaylor]

Still an issue (Nov 2019)