Build modified streamline images

The official image from streamline does not currently work for the arm64
platform. As a temporary measure, the source code and docker build scripts
have been lifted from the official images and are used to build locally.

Some additional modifications are made to reduce overall image size, these
are documented in docker/README.md

docker/streamline-src/public/elite/less/icons/weather-icons/sass/weather-icons.scss

@@ -0,0 +1,30 @@
+/*!
+ *  Weather Icons 2.0
+ *  Updated August 1, 2015
+ *  Weather themed icons for Bootstrap
+ *  Author - Erik Flowers - erik@helloerik.com
+ *  Email: erik@helloerik.com
+ *  Twitter: http://twitter.com/Erik_UX
+ *  ------------------------------------------------------------------------------
+ *  Maintained at http://erikflowers.github.io/weather-icons
+ *
+ *  License
+ *  ------------------------------------------------------------------------------
+ *  - Font licensed under SIL OFL 1.1 -
+ *    http://scripts.sil.org/OFL
+ *  - CSS, LESS and SCSS are licensed under MIT License -
+ *    http://opensource.org/licenses/mit-license.html
+ *  - Documentation licensed under CC BY 3.0 -
+ *    http://creativecommons.org/licenses/by/3.0/
+ *  - Inspired by and works great as a companion with Font Awesome
+ *    "Font Awesome by Dave Gandy - http://fontawesome.io"
+ */
+
+@import 'weather-icons-core.scss';
+@import 'weather-icons-variables.scss';
+@import 'weather-icons-classes.scss';
+// Mappings to various APIs
+@import "mappings/wi-yahoo.scss";
+@import "mappings/wi-forecast-io.scss";
+@import "mappings/wi-wmo4680.scss";
+@import "mappings/wi-owm.scss";