SDDI base Docker build CKAN 2.10.3

[ilchebedelovski]

This PR contains modifications of the following parts in the base image:

• The source image is ckan-base 2.10
• The spatial extension is installed from the official repository
• The runtime is Alpine based

[BWibo]

CKAN 2.10.4 has been released. https://github.com/ckan/ckan/releases/tag/ckan-2.10.4

[BWibo]

What's the status of this PR?

By now, there is an official Debian version of the CKAN images: https://github.com/ckan/ckan-docker-base?
This might fix the issues we have with ckanext-spatial and give us an official base image we can rely on.
We should try them out!

In addition, CKAN 2.11 is on it's way. We need support fot this too, but this should be in a separate pull request.

[MarijaKnezevic]

The developer is currently working on creating the "master plugin", which will solve many problems in future. I have received the first draft from the developer and am now testing the functions to see if anything is still missing.
Once we have finished the master plugin, it would be necessary to complete this PR.

[aleksandralazoroska]

The source image has been updated to ckan-base 2.11

[MarijaKnezevic]

To update to CKAN 2.11, please follow the development idea and logic that was previously discussed with @ilchebedelovski and @BWibo and started here.

[BWibo]

@MarijaKnezevic @aleksandralazoroska
For moving to 2.11 it is most important, that we move away from the keitaronic base images and move to the official ckan base images. That should be possible now, as they are available based on Debian now.
Let's use #64 to discuss this and collect further requirements, that might come up with this change.

[BWibo]

@MarijaKnezevic
This PR is outdated and can be closed, right?

[MarijaKnezevic]

@BWibo yes, this can be closed.
Will not have a release for 2.10 and we will continue to work on updating SDDI to CKAN 2.11 which is current CKAN version