Move to using Amazon Signer, rather than reimplementing.

Gemfile.lock

@@ -2,27 +2,33 @@ PATH
   remote: .
   specs:
     aws_paa (0.1.0)
-      rest-client (~> 2.0)
+      aws-sigv4 (~> 1)
+      http (~> 0.1)
 
 GEM
   remote: https://rubygems.org/
   specs:
+    addressable (2.7.0)
+      public_suffix (>= 2.0.2, < 5.0)
+    awesome_print (1.8.0)
+    aws-eventstream (1.0.3)
+    aws-sigv4 (1.1.0)
+      aws-eventstream (~> 1.0, >= 1.0.2)
+    byebug (11.0.1)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
-    http-accept (1.7.0)
+    http (0.9.9)
+      addressable (~> 2.3)
+      http-cookie (~> 1.0)
+      http-form_data (~> 1.0.1)
+      http_parser.rb (~> 0.6.0)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
-    mime-types (3.2.2)
-      mime-types-data (~> 3.2015)
-    mime-types-data (3.2019.0331)
+    http-form_data (1.0.3)
+    http_parser.rb (0.6.0)
     minitest (5.11.3)
-    netrc (0.11.0)
+    public_suffix (4.0.1)
     rake (10.5.0)
-    rest-client (2.1.0)
-      http-accept (>= 1.7.0, < 2.0)
-      http-cookie (>= 1.0.2, < 2.0)
-      mime-types (>= 1.16, < 4.0)
-      netrc (~> 0.8)
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.6)
@@ -31,8 +37,10 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  awesome_print
   aws_paa!
   bundler (~> 2.0)
+  byebug
   minitest (~> 5.0)
   rake (~> 10.0)