Add white background to electrical svgs

docs/space/electrical/pictures/its_term_1.svg

@@ -64,6 +64,13 @@
      id="g1"
      inkscape:groupmode="layer"
      inkscape:label="1">
+    <rect
+       style="fill:#ffffff;stroke:none;fill-opacity:1"
+       id="background"
+       width="793.92755"
+       height="1122.2551"
+       x="0"
+       y="0" />
     <path
        id="path1"
        d="m 28.346,679.861 h 538.498 v 20.863 H 28.346 Z"

docs/space/electrical/pictures/its_term_2.svg

@@ -62,6 +62,13 @@
      inkscape:groupmode="layer"
      inkscape:label="2"
      transform="translate(-813.92755)">
+    <rect
+       style="fill:#ffffff;stroke:none;fill-opacity:1"
+       id="background"
+       width="793.92755"
+       height="1122.2551"
+       x="813.92755"
+       y="0" />
     <path
        id="path230"
        d="m 28.346,792.85 h 538.498 v 20.863 H 28.346 Z"

docs/space/electrical/pictures/its_term_3.svg

@@ -62,6 +62,13 @@
      inkscape:groupmode="layer"
      inkscape:label="3"
      transform="translate(-1627.8551)">
+    <rect
+       style="fill:#ffffff;stroke:none;fill-opacity:1"
+       id="background"
+       width="793.92755"
+       height="1122.2551"
+       x="1627.8551"
+       y="0" />
     <path
        id="path260"
        d="m 28.091,679.861 h 535.72 v 20.863 H 28.091 Z"

docs/space/electrical/pictures/its_term_4.svg

@@ -65,6 +65,13 @@
      inkscape:groupmode="layer"
      inkscape:label="4"
      transform="translate(-2441.7828)">
+    <rect
+       style="fill:#ffffff;stroke:none;fill-opacity:1"
+       id="background"
+       width="793.92755"
+       height="1122.2551"
+       x="2441.7828"
+       y="0" />
     <path
        id="path495"
        d="m 28.091,679.861 h 535.72 v 20.863 H 28.091 Z"