Full log pipeline to monasca-docker.
Pipeline is defined in docker-compose extensions
`log-pipeline.yml` to minimize an impact on
metric pipeline.

log-pipeline features:

* monasca-log-{api,persister,transformer,metrics}
* elasticsearch + template loading
* kibana

Following commit completes several items:

* added build.yml to integrate into existing CI
* removed all images, apart from master and stable/ocata
* made constraints control a little bit easier with just
  contstrains branch variable

Previously tags were build in wrong way.
Now they are correctly written using `:` as
prefix

Introducing 3 new checkpoints for
monasca-log-api docker image:

- REBUILD_DEPENDENCIES
- REBUILD_CHECKOUT
- REBUILD_CONFIG

Commit adjusts monasca-log-{metrics,persister,transformer}
to:

* include build.yml to be picked up by CI
* shortened images names (removed monasca- prefix)

Commits introduces build checkpoints for:

* monasca-log-metrics
* monasca-log-persister
* monasca-log-transformer

log-pipeline.yml includes bad references
to monasca-log-{metrics,transformer,persister} images

Right now it is possible to enable or disable
monasca-kibana-plugin with environment variable
MONASCA_PLUGIN_ENABLED.

By default the plugin is disabled, to allow
to access Kibana.

* removed FROM python image, using alpine instead and
installing Python by hand
* removed one REBUILD_ step, for now it is better to keep
usage of these low until newer docker is available in travis

All images for monasca-docker should be placed
under monasca namespace

monasca-api variable for the port name starts with
`MONASCA_CONTAINER_` prefix. Make equaivalent log-api
variable to follow the same principle.

Changed the name of the image to elasticsearch-init
to match other init containers. Need to tweak image a bit,
as usage of it is unclear at the moment.

Instead of specyfying the name of the template
manually, allow to get the TPL name from the mounted file.
In the same time it allows to uplaod multiple templates
at once.

Added documentation bits for:

* monasca-log-persister
* monasca-log-transformer

Use monasca/python for application installation
inside the container.

Being explic in build.yml

Now, when there is a separate image to create topic
in kafka, log pipeline should now affect the metric
deployment.

Same as monasca-api, monasca-log-api should use memcache
to speed up token related operations.