cubicweb #1806935 modconcat load the whole concatenated file in memory [resolved]

while it could simply write file per file.

prioritynormal
typebug
done in3.13.1
load0.100
load left0.000
closed by#bc2d690b97bf [etwist, modconcat] closes #1806935: directly write data, don't put the whole concatenated thing in memory