Configure web front-end via command line interface about ck

[psyhtest]

With the capability to set up ${WFE_HOST} and ${WFE_PORT} explicitly, it may be worth also updating the ck setup kernel --wfe dialogue e.g.

=======================================================================
Loading current configuration ...
=======================================================================
*** Web front end control (through CK web server or third-party web server and CK php connector) ***

Current web front-end host: localhost
Current web front-end port: 3344
Current web front-end template: default

Enter new web front-end host (Enter to keep previous):
Enter new web front-end port (Enter to keep previous):
Enter new web front-end template (Enter to keep previous): 

[psyhtest]

With the latest CK changes (in particular, 8fcd77fc, a container can be started with e.g.:

$ docker run --rm -it -p ${WFE_PORT}:${CK_PORT} \
  --env CK_PORT=${CK_PORT} \
  --env WFE_PORT=${WFE_PORT} \
  --env WFE_HOST=${WFE_HOST} \
  ctuning/ck-ubuntu-16.04
Starting CK web service on 172.17.0.2:3355 (configured for access at 192.168.0.65:3344) ...

Once the CK changes are more thoroughly tested and stabilised, this issue can be closed.

[psyhtest]

An experimental CK Docker image is now available at a public repository:

$ docker pull ctuning/ck-ubuntu-16.04

The CK web service can be run locally and accessed at http://localhost:3344/ as follows:

$ docker run --rm -it ctuning/ck-ubuntu-16.04

The CK web service can be run on a remote server (at an address ${WFE_HOST} and with an opened port ${WFE_PORT}) and accessed at ${WFE_HOST}:${WFE_PORT} as follows:

$ export WFE_HOST=123.456.0.78 WFE_PORT=9999 CK_PORT=3344
$ docker run --rm -it -p ${WFE_PORT}:${CK_PORT} \
  --env WFE_HOST=${WFE_HOST} --env WFE_PORT=${WFE_PORT} --env CK_PORT=${CK_PORT} \
  ctuning/ck-ubuntu-16.04
Starting CK web service on 172.17.0.2:3344 (configured for access at 123.456.0.78:9999) ...

NB: The ${CK_PORT} variable must be defined but its value is inconsequential.