shelve: directly handle the abort process Shelve is currently sub-contracting some of its work to the rebase extension. In order to make shelve more independent and flexible we would like shelve to handle the parent alignment directly. This change starts with the simplest bits, handling the abort process. It turns out we have all the necessary bits in the `shelvestate` file. So we do not need anything from the interrupted rebase. As a nice side effect, a test about missing `shelverebasestate` state file now behave better. Differential Revision: https://phab.mercurial-scm.org/D3688

shelve: check the actual shelvestate in morestatus The rebasestate is a lower level implementation details that we are trying to remove. Differential Revision: https://phab.mercurial-scm.org/D3687

packaging: dynamically define make targets We currently have make boilerplate for each instance of a distro's release. This is redundant, annoying to maintain, and prone to errors. This commit defines variables holding available releases for various distros. We then iterate through the list and dynamically define make targets. Differential Revision: https://phab.mercurial-scm.org/D3761

packaging: don't write files for templatized Dockerfiles Now that Docker image building is implemented in Python and we can perform template substitution in memory, we don't need to write out produced Dockerfiles to disk. Differential Revision: https://phab.mercurial-scm.org/D3760