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/buttons.less

@@ -0,0 +1,166 @@
+//
+// Buttons
+// --------------------------------------------------
+
+
+// Base styles
+// --------------------------------------------------
+
+.btn {
+  display: inline-block;
+  margin-bottom: 0; // For input.btn
+  font-weight: @btn-font-weight;
+  text-align: center;
+  vertical-align: middle;
+  touch-action: manipulation;
+  cursor: pointer;
+  background-image: none; // Reset unusual Firefox-on-Android default style; see https://github.com/necolas/normalize.css/issues/214
+  border: 1px solid transparent;
+  white-space: nowrap;
+  .button-size(@padding-base-vertical; @padding-base-horizontal; @font-size-base; @line-height-base; @btn-border-radius-base);
+  .user-select(none);
+
+  &,
+  &:active,
+  &.active {
+    &:focus,
+    &.focus {
+      .tab-focus();
+    }
+  }
+
+  &:hover,
+  &:focus,
+  &.focus {
+    color: @btn-default-color;
+    text-decoration: none;
+  }
+
+  &:active,
+  &.active {
+    outline: 0;
+    background-image: none;
+    .box-shadow(inset 0 3px 5px rgba(0,0,0,.125));
+  }
+
+  &.disabled,
+  &[disabled],
+  fieldset[disabled] & {
+    cursor: @cursor-disabled;
+    .opacity(.65);
+    .box-shadow(none);
+  }
+
+  a& {
+    &.disabled,
+    fieldset[disabled] & {
+      pointer-events: none; // Future-proof disabling of clicks on `<a>` elements
+    }
+  }
+}
+
+
+// Alternate buttons
+// --------------------------------------------------
+
+.btn-default {
+  .button-variant(@btn-default-color; @btn-default-bg; @btn-default-border);
+}
+.btn-primary {
+  .button-variant(@btn-primary-color; @btn-primary-bg; @btn-primary-border);
+}
+// Success appears as green
+.btn-success {
+  .button-variant(@btn-success-color; @btn-success-bg; @btn-success-border);
+}
+// Info appears as blue-green
+.btn-info {
+  .button-variant(@btn-info-color; @btn-info-bg; @btn-info-border);
+}
+// Warning appears as orange
+.btn-warning {
+  .button-variant(@btn-warning-color; @btn-warning-bg; @btn-warning-border);
+}
+// Danger and error appear as red
+.btn-danger {
+  .button-variant(@btn-danger-color; @btn-danger-bg; @btn-danger-border);
+}
+
+
+// Link buttons
+// -------------------------
+
+// Make a button look and behave like a link
+.btn-link {
+  color: @link-color;
+  font-weight: normal;
+  border-radius: 0;
+
+  &,
+  &:active,
+  &.active,
+  &[disabled],
+  fieldset[disabled] & {
+    background-color: transparent;
+    .box-shadow(none);
+  }
+  &,
+  &:hover,
+  &:focus,
+  &:active {
+    border-color: transparent;
+  }
+  &:hover,
+  &:focus {
+    color: @link-hover-color;
+    text-decoration: @link-hover-decoration;
+    background-color: transparent;
+  }
+  &[disabled],
+  fieldset[disabled] & {
+    &:hover,
+    &:focus {
+      color: @btn-link-disabled-color;
+      text-decoration: none;
+    }
+  }
+}
+
+
+// Button Sizes
+// --------------------------------------------------
+
+.btn-lg {
+  // line-height: ensure even-numbered height of button next to large input
+  .button-size(@padding-large-vertical; @padding-large-horizontal; @font-size-large; @line-height-large; @btn-border-radius-large);
+}
+.btn-sm {
+  // line-height: ensure proper height of button next to small input
+  .button-size(@padding-small-vertical; @padding-small-horizontal; @font-size-small; @line-height-small; @btn-border-radius-small);
+}
+.btn-xs {
+  .button-size(@padding-xs-vertical; @padding-xs-horizontal; @font-size-small; @line-height-small; @btn-border-radius-small);
+}
+
+
+// Block button
+// --------------------------------------------------
+
+.btn-block {
+  display: block;
+  width: 100%;
+}
+
+// Vertically space out multiple block buttons
+.btn-block + .btn-block {
+  margin-top: 5px;
+}
+
+// Specificity overrides
+input[type="submit"],
+input[type="reset"],
+input[type="button"] {
+  &.btn-block {
+    width: 100%;
+  }
+}