Add configuration:
```
bundle:
lock:
enabled: true
force: false
```
The force field can be set by passing the `--force` argument to `bricks
bundle deploy`. Doing so means the deployment lock is acquired even if
it is currently held. This should only be used in exceptional cases
(e.g. a previous deployment has failed to release the lock).
Summary:
* All remote path arguments for deployer and locker are now relative to
root specified at initialization
* The workspace client is now a struct field so it doesn't have to be
passed around
Serge Smertin
Pieter Noordhuis
Kartik Gupta
shreyas-goenka