builtin-remote: new show output style

builtin-remote: new show output style

The existing output of "git remote show <remote>" is too verbose for the
information it provides. This patch teaches it to provide more
information in less space.

The output for push refspecs is addressed in the next patch.

Before the patch:

$ git remote show origin
* remote origin
  URL: git://git.kernel.org/pub/scm/git/git.git
  HEAD branch: master
  Remote branch merged with 'git pull' while on branch master
    master
  Remote branch merged with 'git pull' while on branch next
    next
  Remote branches merged with 'git pull' while on branch octopus
    foo bar baz frotz
  New remote branch (next fetch will store in remotes/origin)
    html
  Stale tracking branch (use 'git remote prune')
    bogus
  Tracked remote branches
    maint
    man
    master
    next
    pu
    todo

After this patch:

$ git remote show origin
* remote origin
  URL: git://git.kernel.org/pub/scm/git/git.git
  HEAD branch: master
  Remote branches:
    bogus  stale (use 'git remote prune' to remove)
    html   new (next fetch will store in remotes/origin)
    maint  tracked
    man    tracked
    master tracked
    next   tracked
    pu     tracked
    todo   tracked
  Local branches configured for 'git pull':
    master  rebases onto remote master
    next    rebases onto remote next
    octopus  merges with remote foo
                and with remote bar
                and with remote baz
                and with remote frotz

$ git remote show origin -n
* remote origin
  URL: git://git.kernel.org/pub/scm/git/git.git
  HEAD branch: (not queried)
  Remote branches: (status not queried)
    bogus
    maint
    man
    master
    next
    pu
    todo
  Local branches configured for 'git pull':
    master  rebases onto remote master
    next    rebases onto remote next
    octopus  merges with remote foo
                and with remote bar
                and with remote baz
                and with remote frotz

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>