templates: add __init__.py files to templates/ dirs This is necessary for them to be loaded with `importlib.resources`, which we want to do for PyOxidizer and similar. `importlib.resources` cannot read resources from submodules (`resources.open_binary('mercurial.templates', 'coal/map')` is not valid), so we need one `__init__.py` per directory. Differential Revision: https://phab.mercurial-scm.org/D8854

merge with stable

localrepo: abort creating a shared repo if the source does not have store We cannot create a shared repository without a store IIUC. Let's abort in such cases. Differential Revision: https://phab.mercurial-scm.org/D8772

localrepo: only use 'bookmarksinstore' requirement if we have 'store' This adds check that whether we have the 'store' requirement or not. If we don't have that, we skip adding the 'bookmarksinstore' requirement and warn user about it. Differential Revision: https://phab.mercurial-scm.org/D8771

mergeresult: make actionmapping a dict of dict instead of dict of lists This makes deleting a specific filename entry faster and easier. Differential Revision: https://phab.mercurial-scm.org/D8837

largefiles: introduce a constant for 'lfmr' action It's better to use a dedicated constant instead of a string which makes pretty less sense. Differential Revision: https://phab.mercurial-scm.org/D8836

largefiles: override merge.emptyactions() to include `lfmr` I found it weird that we were not already doing this. I encountered this while using `emptyactions()` in mergeresult() class. Differential Revision: https://phab.mercurial-scm.org/D8835