Use the local hosted fonts (apache#22)

Fix issues reported from: https://whimsy.apache.org/pods/project/pegasus

Follow the rule [1] of:

> Can I use Google Fonts?
You can use Google Fonts, but please host the fonts on ASF servers.
>
> ASF projects don’t have any reason to load Google Fonts from Google servers. Even [performance wise](https://wicki.io/posts/2020-11-goodbye-google-fonts/), there is no reason to use Google CDNs.
>
> To prevent any data being transmitted to a third party, [download the fonts and host them with your project website](https://github.com/google/fonts#self-host-fonts-available-from-google-fonts).

1. https://privacy.apache.org/faq/committers.html

_sass/_main.scss

@@ -1,8 +1,23 @@
 @charset "utf-8";
+
 // for apache pegasus title
-@import url(//fonts.googleapis.com/css?family=Patua+One);
-@import url(//fonts.googleapis.com/css?family=Ubuntu+Mono);
-@import url(//fonts.googleapis.com/css?family=Titillium+Web);
+// Patua One
+@font-face {
+  font-family: 'Patua One';
+  src: url(/assets/fonts/PatuaOne-Regular.ttf)
+}
+
+// Ubuntu Mono
+@font-face {
+  font-family: 'Ubuntu Mono';
+  src: url(/assets/fonts/UbuntuMono-Regular.ttf)
+}
+
+// Titillium Web
+@font-face {
+  font-family: 'Titillium Web';
+  src: url(/assets/fonts/TitilliumWeb-Regular.ttf)
+}
 
 $primary: #188eac !default;
 $info: #419eda;