Move some Ansible config out of scripts and into ansible.cfg

My immediate motivation is that I'm going to try turning on the
pipelining setting, to improve performance, and I'd like to have the
consistent place to put it! But also, I like standardizing our setup a
bit more, too

bin/deploy:push

@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 # Deploy a new version to production, using the Ansible playbook in `deploy/deploy.yml`.
 # This skips the build step that normally runs when you just call `bin/deploy`.
-ansible-playbook -i deploy/inventory.cfg deploy/deploy.yml
+cd $(dirname $0)/../deploy && ansible-playbook deploy.yml

bin/deploy:setup

@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 # Set up the deployment environment, using the Ansible playbook in `deploy/setup.yml`.
 echo $'Setup requires you to become the root user. You\'ll need to enter the password for your account on the remote web server below, and you must be part of the `sudo` user group.'
-ansible-playbook -K -i deploy/inventory.cfg deploy/setup.yml
+cd $(dirname $0)/../deploy && ansible-playbook -K setup.yml

deploy/ansible.cfg

@@ -0,0 +1,2 @@
+[defaults]
+inventory = inventory.cfg