patchbomb: add a 'bundletype' config under 'patchbomb' patchbomb relies on the 'hg bundle' command to generate an attached bundle using --bundle. However, while 'hg bundle' has a --type option, patchbomb did not. This is becoming very relevant since we are about to issue bundle2 for general-delta repository. This was tracked as issue4863

import: allow processing of extra part header after import As we have a way for extension to add more header, we need a way for them to actually process them. We add a basic hook point to do extra work after the import have been committed.