Change fonts to use what VSCode does (Closes #843)

packages/insomnia-app/app/ui/css/constants/fonts.less

@@ -1,2 +1,2 @@
-@font-monospace: 'Source Code Pro', Menlo, Monaco, 'Ubuntu Mono', Consolas, 'Lucida Console', 'Courier New', monospace;
-@font-default: 'Open Sans', sans-serif;
+@font-monospace: Menlo, Monaco, Consolas, "Droid Sans Mono", "Courier New", monospace, "Droid Sans Fallback";
+@font-default: -apple-system, BlinkMacSystemFont, "Segoe WPC", "Segoe UI", "HelveticaNeue-Light", "Ubuntu", "Droid Sans", sans-serif;;

packages/insomnia-app/app/ui/css/index.less

@@ -5,7 +5,6 @@
 /* Libs */
 @import 'lib/chrome/platform_app.css';
 @import 'lib/fontawesome/css/font-awesome.css';
-@import 'lib/fonts/open-sans.css';
 
 /* Boilerplate */
 @import 'reset';

packages/insomnia-app/app/ui/css/lib/fonts/open-sans.css

@@ -1,78 +0,0 @@
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/Light/OpenSans-Light.woff2?v=1.1.0");
-  font-weight: 300;
-  font-style: normal;
-}
-
-/* END Light */
-/* BEGIN Light Italic */
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/LightItalic/OpenSans-LightItalic.woff2?v=1.1.0");
-  font-weight: 300;
-  font-style: italic;
-}
-
-/* END Light Italic */
-/* BEGIN Regular */
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/Regular/OpenSans-Regular.woff2?v=1.1.0");
-  font-weight: normal;
-  font-style: normal;
-}
-
-/* END Regular */
-/* BEGIN Italic */
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/Italic/OpenSans-Italic.woff2?v=1.1.0");
-  font-weight: normal;
-  font-style: italic;
-}
-
-/* END Italic */
-/* BEGIN Semibold */
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/Semibold/OpenSans-Semibold.woff2?v=1.1.0");
-  font-weight: 600;
-  font-style: normal;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/SemiboldItalic/OpenSans-SemiboldItalic.woff2?v=1.1.0");
-  font-weight: 600;
-  font-style: italic;
-}
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/Bold/OpenSans-Bold.woff2?v=1.1.0") format("woff2");
-  font-weight: bold;
-  font-style: normal;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/BoldItalic/OpenSans-BoldItalic.woff2?v=1.1.0");
-  font-weight: bold;
-  font-style: italic;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/ExtraBold/OpenSans-ExtraBold.woff2?v=1.1.0");
-  font-weight: 800;
-  font-style: normal;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  src: url("./fonts/ExtraBoldItalic/OpenSans-ExtraBoldItalic.woff2?v=1.1.0");
-  font-weight: 800;
-  font-style: italic;
-}
-
-