RSS icon fixes (#24476)

Fix regression from https://github.com/go-gitea/gitea/pull/24471 where
CSS rules for `.icon.grey` were removed which were in use by the RSS
icons.

Gave them their own class instead, removed a wrapper and also fixed
vertical alignment on them. Additionally, did a few related fixes on the
org header for alignment.

Fixes: https://github.com/go-gitea/gitea/issues/24584

<img width="196" alt="Screenshot 2023-05-01 at 22 39 40"
src="https://user-images.githubusercontent.com/115237/235528228-959e2385-c1d2-4d5c-baec-e3784d459653.png">
<img width="216" alt="Screenshot 2023-05-01 at 22 44 20"
src="https://user-images.githubusercontent.com/115237/235528231-95cbff86-5672-48eb-b214-8bdcefa1612c.png">
<img width="120" alt="Screenshot 2023-05-01 at 22 56 36"
src="https://user-images.githubusercontent.com/115237/235529844-b94ab554-3259-4d0c-b040-82aed7d1a111.png">


<img width="372" alt="Screenshot 2023-05-01 at 22 54 25"
src="https://user-images.githubusercontent.com/115237/235529744-1a9c201b-5692-4122-9765-2f201a322a9e.png">
<img width="477" alt="Screenshot 2023-05-01 at 22 55 28"
src="https://user-images.githubusercontent.com/115237/235529748-62188554-9927-42ef-bc94-7052bce266e2.png">

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/release/list.tmpl

@@ -3,14 +3,7 @@
 	{{template "repo/header" .}}
 	<div class="ui container">
 		{{template "base/alert" .}}
-		{{template "repo/sub_menu_release_tag" .}}
-
-		{{if .CanCreateRelease}}
-			<a class="ui right small green button" href="{{$.RepoLink}}/releases/new">
-				{{.locale.Tr "repo.release.new_release"}}
-			</a>
-		{{end}}
-
+		{{template "repo/release_tag_header" .}}
 		<ul id="release-list">
 			{{range $idx, $release := .Releases}}
 				<li class="ui grid">