Doc-reboot - added translation support with po4a

Hi, here is a Pull Request adding: * adoc to pot * pot -> po (it updates existing translation files) * po -> adoc (we have to agree on a threshold, I used 0 by default) * zanata push/pull https://pagure.io/docs-reboot/install-guide/pull-request/2 I add my name as point of contact on the script, but I reuse most of Brian's work. Please note the translators also need to translate _topic_map.yml, but I assume we should probably move this file into "en-GB". Can we do this? https://pagure.io/docs-reboot/install-guide/issue/3 I'm afraid my laptop is crashing too much at the moment to go really further, this code needs a little more testing, but I'm confident it's going to work very fine. We'll have to add language switch (please use a more obvious location than what we have for websites ;)). Have a nice day, -- Jean-Baptiste Holcroft