Button and color enhancements (#24989)

- Various corrections to button styles, especially secondary
- Remove focus highlight, it's annoying when it stays on button after
press
- Clearly define ghost and link buttons with demos in devtest
- Remove black, grey and tertiary buttons, they should not be used
- Make `arc-green` slightly darker

<img width="1226" alt="image"
src="https://github.com/go-gitea/gitea/assets/115237/8d89786a-01ab-40f8-ae5a-e17f40e35084">
<img width="1249" alt="image"
src="https://github.com/go-gitea/gitea/assets/115237/83651e6d-3c27-46ff-b8bd-ff344d70e949">

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

web_src/js/components/RepoActionView.vue

@@ -14,7 +14,7 @@
         <button class="ui basic small compact button red" @click="cancelRun()" v-else-if="run.canCancel">
           {{ locale.cancel }}
         </button>
-        <button class="ui basic small compact button secondary gt-mr-0" @click="rerun()" v-else-if="run.canRerun">
+        <button class="ui basic small compact button gt-mr-0" @click="rerun()" v-else-if="run.canRerun">
           {{ locale.rerun_all }}
         </button>
       </div>
@@ -70,7 +70,7 @@
           </div>
           <div class="job-info-header-right">
             <div class="ui top right pointing dropdown custom jump item" @click.stop="menuVisible = !menuVisible" @keyup.enter="menuVisible = !menuVisible">
-              <button class="ui button button-ghost gt-p-3">
+              <button class="btn gt-interact-bg gt-p-3">
                 <SvgIcon name="octicon-gear" :size="18"/>
               </button>
               <div class="menu transition action-job-menu" :class="{visible: menuVisible}" v-if="menuVisible" v-cloak>