Similar to ostree_repo_write_archive_to_mtree(), but takes
a file descriptor to read the archive from instead of mandating
a file path.
Usefull for importing archives into an OSTree repo over a socket
or from standard input in command line tools.
Closes: #1862
Approved by: jlebon
This is especially interesting for the versioning symbols themselves,
as it is an indicator of when applications using introspection information
can start to use a symbol in the library to check if they have a
recent enough version of OSTree to use.
Closes: #932
Approved by: cgwalters
Tristan Van Berkom