Add new sponsors: Allegro and SaltStack.

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>
Rename "sponsor" to "partner".

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>
Merge pull request #993 from kwilczynski/master

Update DevOpsDays Warsaw event page.