Replace sqitch.conf with a template with customizable database URIs

Databases are no longer directly accessible, and each environment may have connections to ID3C configured differently, so replacing hard coded URIs with placeholders. `sqitch.template.conf` should be copied to `sqitch.conf` and the database connection URIs should updated in that file prior to running sqitch commands.

.gitignore

@@ -10,7 +10,7 @@
 !/Pipfile.lock
 !/pytest.ini
 !/setup.py
-!/sqitch.conf
+!/sqitch.template.conf
 !/wsgi.py
 
 # and these directories

sqitch.conf → sqitch.template.conf

@@ -18,10 +18,10 @@
 	target = dev
 
 [target "dev"]
-	uri = db:pg:seattleflu
+	uri = db:pg://<USER>@<HOST>:<PORT>/seattleflu
 
 [target "testing"]
-	uri = db:pg://testing.db.seattleflu.org/testing
+	uri = db:pg://<USER>@<HOST>:<PORT>/testing
 
 [target "production"]
-	uri = db:pg://production.db.seattleflu.org/production
+	uri = db:pg://<USER>@<HOST>:<PORT>/production