Add x-maintenance-intent for Irmin packages

[art-w]

The deprecated irmin-mem and irmin-unix packages were moved to the main irmin package some time ago (under irmin.mem and irmin.unix).

[hannesm]

Thanks! :)

for imin-mem and irmin-unix a flags: deprecated in all versions would be fine as well, but the x-maintenance-intent: [ "(none)" ] is good as well.

There's no need for specifying the x-reason-for-archival, this will be added when the package(s) are moved to opam-repository-archive.

[art-w]

Ok sure! Thanks for the clarifications :)

[mseri]

Thanks

[hannesm]

I don't think the last commit (adding sources to irmin-unix) is necessary -- since back then irmin used optional dependencies, and the irmin-unix was just a package depending on irmin and the optional dependencies to get irmin.unix built -- i.e. irmin-unix didn't install anything (and there's no ocamlfind package for irmin-unix) -- so no sources are necessary.

[art-w]

Yeah hm you're right I removed that last commit.