Legacy utility to handle MLA 1 and 2

According to https://github.com/ANSSI-FR/MLA/issues/208#issue-2422775459, this issue concerns `mlar-legacy`. Upgrade mechanism will consist in specific versions of `mlar`: - `mlar-legacy`: mlar version that will support extraction (and repair) for MLA 1 and MLA 2 in addition with everything `mlar` 2 has : best option for current pipelines using MLA - this issue - `mlar-upgrade`: mlar archive upgrader from MLA 1 to MLA 2 : option if you decide to only support MLA 2 in your pipelines - [this issue](https://github.com/ANSSI-FR/MLA/issues/208)