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/popovers.less

@@ -0,0 +1,131 @@
+//
+// Popovers
+// --------------------------------------------------
+
+
+.popover {
+  position: absolute;
+  top: 0;
+  left: 0;
+  z-index: @zindex-popover;
+  display: none;
+  max-width: @popover-max-width;
+  padding: 1px;
+  // Our parent element can be arbitrary since popovers are by default inserted as a sibling of their target element.
+  // So reset our font and text properties to avoid inheriting weird values.
+  .reset-text();
+  font-size: @font-size-base;
+
+  background-color: @popover-bg;
+  background-clip: padding-box;
+  border: 1px solid @popover-fallback-border-color;
+  border: 1px solid @popover-border-color;
+  border-radius: @border-radius-large;
+  .box-shadow(0 5px 10px rgba(0,0,0,.2));
+
+  // Offset the popover to account for the popover arrow
+  &.top     { margin-top: -@popover-arrow-width; }
+  &.right   { margin-left: @popover-arrow-width; }
+  &.bottom  { margin-top: @popover-arrow-width; }
+  &.left    { margin-left: -@popover-arrow-width; }
+}
+
+.popover-title {
+  margin: 0; // reset heading margin
+  padding: 8px 14px;
+  font-size: @font-size-base;
+  background-color: @popover-title-bg;
+  border-bottom: 1px solid darken(@popover-title-bg, 5%);
+  border-radius: (@border-radius-large - 1) (@border-radius-large - 1) 0 0;
+}
+
+.popover-content {
+  padding: 9px 14px;
+}
+
+// Arrows
+//
+// .arrow is outer, .arrow:after is inner
+
+.popover > .arrow {
+  &,
+  &:after {
+    position: absolute;
+    display: block;
+    width: 0;
+    height: 0;
+    border-color: transparent;
+    border-style: solid;
+  }
+}
+.popover > .arrow {
+  border-width: @popover-arrow-outer-width;
+}
+.popover > .arrow:after {
+  border-width: @popover-arrow-width;
+  content: "";
+}
+
+.popover {
+  &.top > .arrow {
+    left: 50%;
+    margin-left: -@popover-arrow-outer-width;
+    border-bottom-width: 0;
+    border-top-color: @popover-arrow-outer-fallback-color; // IE8 fallback
+    border-top-color: @popover-arrow-outer-color;
+    bottom: -@popover-arrow-outer-width;
+    &:after {
+      content: " ";
+      bottom: 1px;
+      margin-left: -@popover-arrow-width;
+      border-bottom-width: 0;
+      border-top-color: @popover-arrow-color;
+    }
+  }
+  &.right > .arrow {
+    top: 50%;
+    left: -@popover-arrow-outer-width;
+    margin-top: -@popover-arrow-outer-width;
+    border-left-width: 0;
+    border-right-color: @popover-arrow-outer-fallback-color; // IE8 fallback
+    border-right-color: @popover-arrow-outer-color;
+    &:after {
+      content: " ";
+      left: 1px;
+      bottom: -@popover-arrow-width;
+      border-left-width: 0;
+      border-right-color: @popover-arrow-color;
+    }
+  }
+  &.bottom > .arrow {
+    left: 50%;
+    margin-left: -@popover-arrow-outer-width;
+    border-top-width: 0;
+    border-bottom-color: @popover-arrow-outer-fallback-color; // IE8 fallback
+    border-bottom-color: @popover-arrow-outer-color;
+    top: -@popover-arrow-outer-width;
+    &:after {
+      content: " ";
+      top: 1px;
+      margin-left: -@popover-arrow-width;
+      border-top-width: 0;
+      border-bottom-color: @popover-arrow-color;
+    }
+  }
+
+  &.left > .arrow {
+    top: 50%;
+    right: -@popover-arrow-outer-width;
+    margin-top: -@popover-arrow-outer-width;
+    border-right-width: 0;
+    border-left-color: @popover-arrow-outer-fallback-color; // IE8 fallback
+    border-left-color: @popover-arrow-outer-color;
+    &:after {
+      content: " ";
+      right: 1px;
+      border-right-width: 0;
+      border-left-color: @popover-arrow-color;
+      bottom: -@popover-arrow-width;
+    }
+  }
+}