Remove remaining fontawesome usage in templates (#15952)

Can not remove the dependency yet because easymde depends on it.

web_src/less/_base.less

@@ -1162,12 +1162,6 @@ footer {
     padding: 0 .5rem;
     max-width: calc(100vw - 1rem) !important;
 
-    .fa {
-      width: 16px;
-      text-align: center;
-      color: var(--color-primary);
-    }
-
     .links > * {
       border-left: 1px solid var(--color-secondary);
       padding-left: 8px;

web_src/less/_user.less

@@ -34,8 +34,7 @@
               border-bottom: 1px solid var(--color-secondary);
             }
 
-            .svg,
-            .fa {
+            .svg {
               margin-left: 1px;
               margin-right: 5px;
             }

web_src/svg/fontawesome-openid.svg

@@ -0,0 +1,3 @@
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" width="448" height="448" viewBox="0 0 448 448">
+  <path d="M271.5 0v384l-68 32c-115-10.25-203.5-71.5-203.5-145.75 0-71.5 82.5-131 191.75-144.25v43c-71.5 12.5-124 53-124 101.25 0 51 58.5 93.25 135.75 103v0-340zM438.75 145.5l9.25 97.5-131.25-28.5 36.75-20.75c-19.5-11.5-43.5-20-70-24.75v-43c46.25 5.5 87.75 19.5 120.25 39.25z"></path>
+</svg>

web_src/svg/fontawesome-windows.svg

@@ -0,0 +1,3 @@
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" width="416" height="448" viewBox="0 0 416 448">
+  <path d="M170.5 251.5v162.75l-170.5-23.5v-139.25h170.5zM170.5 65.75v164.75h-170.5v-141.25zM416 251.5v196.5l-226.75-31.25v-165.25h226.75zM416 32v198.5h-226.75v-167.25z"></path>
+</svg>