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/bootstrap/less/code.less

@@ -0,0 +1,69 @@
+//
+// Code (inline and block)
+// --------------------------------------------------
+
+
+// Inline and block code styles
+code,
+kbd,
+pre,
+samp {
+  font-family: @font-family-monospace;
+}
+
+// Inline code
+code {
+  padding: 2px 4px;
+  font-size: 90%;
+  color: @code-color;
+  background-color: @code-bg;
+  border-radius: @border-radius-base;
+}
+
+// User input typically entered via keyboard
+kbd {
+  padding: 2px 4px;
+  font-size: 90%;
+  color: @kbd-color;
+  background-color: @kbd-bg;
+  border-radius: @border-radius-small;
+  box-shadow: inset 0 -1px 0 rgba(0,0,0,.25);
+
+  kbd {
+    padding: 0;
+    font-size: 100%;
+    font-weight: bold;
+    box-shadow: none;
+  }
+}
+
+// Blocks of code
+pre {
+  display: block;
+  padding: ((@line-height-computed - 1) / 2);
+  margin: 0 0 (@line-height-computed / 2);
+  font-size: (@font-size-base - 1); // 14px to 13px
+  line-height: @line-height-base;
+  word-break: break-all;
+  word-wrap: break-word;
+  color: @pre-color;
+  background-color: @pre-bg;
+  border: 1px solid @pre-border-color;
+  border-radius: @border-radius-base;
+
+  // Account for some code outputs that place code tags in pre tags
+  code {
+    padding: 0;
+    font-size: inherit;
+    color: inherit;
+    white-space: pre-wrap;
+    background-color: transparent;
+    border-radius: 0;
+  }
+}
+
+// Enable scrollable blocks of code
+.pre-scrollable {
+  max-height: @pre-scrollable-max-height;
+  overflow-y: scroll;
+}