Add webmention styles and share buttons

- Created a new SCSS file for webmention styles to enhance the appearance of comments and reactions.
- Added HTML partial for share buttons including Twitter, Facebook, LinkedIn, Reddit, and WhatsApp.
- Updated the main SCSS file to include webmention styles and removed the old CSS file for webmentions.
- Updated asset integrity for the compiled CSS file.

static/css/webmention.css

@@ -1,68 +0,0 @@
-#webmentions {
-    margin: 0;
-    position: relative;
-    z-index: 100;
-    line-height: 1.2em;
-}
-
-#webmentions .comments {
-    overflow-x: hidden;
-    overflow-y: scroll;
-}
-
-#webmentions h2 {
-    font-size: medium;
-    margin: 0;
-    padding: 2px;
-}
-
-#webmentions .reacts img {
-    margin: 3px -1ex 8px 0;
-}
-
-#webmentions img.missing {
-    border: dashed black 1px;
-}
-
-#webmentions ul {
-    list-style-type: none;
-    margin: 0;
-    padding: 4px;
-}
-
-#webmentions li {
-    text-indent: -1em;
-    padding-left: 1em;
-}
-
-#webmentions a.reaction {
-    position: relative;
-    text-decoration: none;
-    margin-right: 0;
-    letter-spacing: -1ex;
-    margin-right: 3ex;
-}
-
-#webmentions a.reaction img {
-    max-height: 3em;
-    width: auto;
-    margin-right: -1ex;
-    border-radius: 25%;
-}
-
-#webmentions a.reaction sub {
-    font-size: 50%;
-}
-
-#webmentions .comments li {
-    white-space: nowrap;
-    text-overflow: ellipsis;
-    overflow: hidden;
-}
-
-#webmentions .comments li .text {
-    font-style: italic;
-    text-decoration: none;
-}
-
-