replace AUR packages for git-annex and pandoc

These both have a bunch of haskell dependencies, but now that git-annex
is available in Community enough of the dependencies are shared between
them that it seems worthwhile to do this. Fewer AUR packages is more
better.

roles/git-annex/tasks/main.yml

@@ -1,8 +1,6 @@
 ---
 - name: Install git-annex
-  aur: name=git-annex-bin user={{ user.name }} skip_pgp=yes
-  tags:
-    - aur
+  pacman: name=git-annex state=present
 
 - name: Push git-annex assistant service file
   copy: src=git-annex.service dest=/etc/systemd/system/git-annex@.service

roles/office/tasks/main.yml

@@ -17,9 +17,7 @@
   pacman: name=simple-scan state=present
 
 - name: Install pandoc
-  aur: name=pandoc-bin user={{ user.name }}
-  tags:
-    - aur
+  pacman: name=pandoc state=present
 
 - name: Install masterpdfeditor-qt5
   aur: name=masterpdfeditor-qt5 user={{ user.name }}