Merge branch 'ob/core-attributesfile-in-repository'

The core.attributesfile is intended to be set per repository, but were kept track of by a single global variable in-core, which has been corrected by moving it to per-repository data structure. * ob/core-attributesfile-in-repository: environment: move "branch.autoSetupMerge" into `struct repo_config_values` environment: stop using core.sparseCheckout globally environment: stop storing `core.attributesFile` globally