Revamp repo header (#27760)

Redesign repo header with following new aspects:
- responsive & better-looking repo title
- hide repo button text instead of icons in mobile view
- use same tab style as on explore and org page

<details>
<summary>Before:</summary>


![grafik](57360b77-d43c-49ac-b798-2363c03da7ec)

![grafik](d4117f79-a5f5-4f36-bf65-bbada3e7e73b)

![grafik](e26f967f-e264-4337-9925-3d942e04fd6d)

![grafik](b4683c8d-9c6a-4089-afa7-8dd219e43a46)


</details>

<details>
<summary>After:</summary>


![grafik](8ddbc9f6-53c7-4e4e-bea9-704fd93524ca)

![grafik](c0588aa9-788d-469c-98a0-81484fbd220c)

![grafik](206e931e-404d-4d1b-92ce-908698addfcc)

![grafik](a508f9c8-fadc-4a85-94ba-18796f77e07b)

web_src/css/base.css

@@ -1358,23 +1358,6 @@ img.ui.avatar,
   padding-right: 4.5px;
 }
 
-.repo-title {
-  font-size: 1.5rem;
-  display: flex;
-  align-items: center;
-  flex: 1;
-  word-break: break-all;
-  color: var(--color-text-light);
-}
-
-.repo-title .labels {
-  margin-left: 0.5rem;
-}
-
-.repo-title .labels > * + * {
-  margin-left: 0.5rem;
-}
-
 .activity-bar-graph {
   background-color: var(--color-primary);
   color: var(--color-primary-contrast);