CI - improve our config file and speed up the generation of html and epub
The problem: We tried to use several stages, like: 1 build + 1 deploy. It does not work using artifacts, they are too big (2.5G for html+epub), even compressed (tried with 7z html+epub for 'en' goes from 250M to 170M, we have 9 languages => still 1.5G, and pdf are missing). Moreover it's quite a bad idea to compressed and uncompressed 2.5G I guess.
Ideally we should have 2 builds running in parallel (html/epub) and then deploy.
I have tried the cache mechanism, it does not work (the second build stage will erase the first one).
"cache": https://gitlab.com/joubu/kohadocs/-/jobs/47745271 (same with /cache)
"untracked: true": https://gitlab.com/joubu/kohadocs/pipelines/16091680 - this one worked but I expect random behaviour (need to be confirmed)
Any ideas?