Consolidate Git configuration

Another 72-column wide game of "typography tetris" follows, interspersed
with TODOs and rambling self-reminders that I'm probably going to forget
later anyway:

git-config(1)
-------------

* Replace each different `textconv` handler with a call to a shellscript
  which unifies this whole mess. That one-line wrapper for `docx2txt` is
  retarded and should never have existed in the first place (if only the
  author had defaulted to using STDOUT instead of a .txt file, eh?).

* Add to aforementioned script a diffing helper for comparing compressed
  archives. Make sure to use `bsdtar -vtf` first before trying any other
  solution.

less(1), lynx(1)
----------------

* Leverage `LESSOPEN` to prettyprint JSON and anything quacking like XML
  or SGML. Follow sketchy conventions and name the script `.lessfilter`.

* Configure Lynx's keybindings so it feels like an actual pager program.

* Figure out why Lynx's source-view isn't being reformatted, and fix the
  startpage to show recent browsing history (or at least bookmarks).

Darwinisms
----------

* Separate the macOS-specific crap from the shared stuff so we keep this
  repository DRY and free of copy+pasta. Organise `./etc/install/` so we
  can add OpenBSD-related installer files for quicker station setup.

* Find a way to always extract archives to a single directory unless the
  only top-level file *is* a directory. Kind of like Apple's Finder, but
  without all the "Darwinisms" (__MACOSX, .DS_Store, ._*, etc).

.gitconfig

@@ -1,19 +1,7 @@
 [user]
 	name = Alhadis
 	email = gardnerjohng@gmail.com
-	signingkey = 895D24EE
-[credential]
-	helper = osxkeychain
-[diff]
-	renames = copies
-[diff "word"]
-	textconv = docx2txt
-[diff "exif"]
-	textconv = exiftool -x FileName -x Directory
-[diff "bin"]
-	textconv = hexdump -v -C
-[push]
-	default = simple
+	signingkey = C57044A83594344A
 [core]
 	editor = /usr/local/bin/emacs
 	excludesfile = ~/.files/etc/.gitignore-global
@@ -25,7 +13,29 @@
 	co = checkout
 	r = remote --verbose
 	s = status
+[credential]
+	helper = osxkeychain
+[diff]
+	renames = copies
+[diff "bin"]
+	textconv = hexdump -v -C
+	cachetextconv = true
+[diff "exif"]
+	textconv = exiftool -x FileName -x Directory
+	cachetextconv = true
+[diff "ps"]
+	textconv = ps2ascii
+	cachetextconv = true
+	binary = true
+[diff "odt"]
+	textconv = odt2txt
+	cachetextconv = true
+[diff "docx"]
+	textconv = docx2txt
+	cachetextconv = true
 [filter "lfs"]
 	clean = git-lfs clean -- %f
 	smudge = git-lfs smudge -- %f
 	required = true
+[gpg]
+	program = gpg2

etc/.gitattributes-global

@@ -8,5 +8,6 @@
 *.psd     diff=exif
 
 # Document diffs
-*.docx    diff=word
-*.doc     diff=word
+*.docx    diff=docx
+*.doc     diff=docx
+*.odt     diff=odt