packaging: move most packaging targets to own Makefile
Since we're putting everything packaging under one roof, let's
define the make targets related to packaging there as well.
I didn't move the "osx" target because it is non-trivial.
Some targets did change slightly as part of the move. But it
was mostly around path normalization.
Differential Revision: https://phab.mercurial-scm.org/D3552
https://bz.mercurial-scm.org/1089
$ hg init
$ mkdir a
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ hg ci -m m a
$ mkdir a b
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ cd b
Relative delete:
$ hg ci -m m ../a
$ cd ..