Add apache libcloud

[Kami]

This pull request adds information about Apache Libcloud (including the timeline section).

I also compressed / optimized all other images which didn't appear to be optimized.

[takluyver]

Thanks! Just to check as you deleted the checklist: you've discussed both the end of Python 2 support and signing this statement with any other active maintainers on the project? We try to ensure that no-one is surprised to see their project on the list.

[Checked that @Kami is a main maintainer of libcloud]

[Kami]

@takluyver Thanks.

Yeah I opened a mailing list thread and there were no objections (https://lists.apache.org/thread.html/8ee66655e249f2123cd0353a5910f8f8182bf8a626d83d223d288c53@%3Cdev.libcloud.apache.org%3E).

Libcloud is an Apache project and a "lazy consensus" was used (https://community.apache.org/committers/lazyConsensus.html).

[takluyver]

Great, thanks!