Currently, async workers are started before HTTP interface is available
to get their requests. It fixes by ensuring that async workers are
started after HTTP interface is up.
Essentially we are getting rid of an error message during bootstrap:
ERRO[0000] Could not fetch task error=Get http://127.0.0.1:8080/tasks: dial tcp 127.0.0.1:8080: getsockopt: connection refused
By default, BoltDB will hang while waiting to acquire lock to the
datafile, thus the users might find themselves waiting for something
but not what. The added timeout aims inform use about what's
happening.
Also this renames MQADR to TASKSRV, refactor configuration to read
environment variables. RunAsyncRunner now fills the gaps when
parsing TASKSRV.
Fixes#119
