ui: make the large file warning limit fully configurable
While add --large can be used to override it selectively, often enough
the user simply doesn't care about machines with less than 100MB RAM or
so, so make it possible to just specify a larger limit in hgrc.
Differential Revision: https://phab.mercurial-scm.org/D3893
#require symlink
https://bz.mercurial-scm.org/1438
$ hg init
$ ln -s foo link
$ hg add link
$ hg ci -mbad link
$ hg rm link
$ hg ci -mok
$ hg diff -g -r 0:1 > bad.patch
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import --no-commit bad.patch
applying bad.patch
$ hg status
R link
? bad.patch