Project board improvements (#15429)

* Project board improvements

- Fix link colors
- Extract CSS to own file
- Various minor tweaks to make it look better

Fixes: https://github.com/go-gitea/gitea/issues/15424
Fixes: https://github.com/go-gitea/gitea/issues/15506
Fixes: https://github.com/go-gitea/gitea/pull/15511

* fix squashed cards on small view area

* more css fixes, add second row from issue list

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

web_src/less/_repository.less

@@ -2940,82 +2940,6 @@ tbody.commit-list {
   padding-top: 0 !important;
 }
 
-.board {
-  display: flex;
-  flex-direction: row;
-  flex-wrap: nowrap;
-  overflow-x: auto;
-  margin: 0 .5em;
-}
-
-.board-column {
-  background-color: rgba(0, 0, 0, .05) !important;
-  border: 1px solid var(--color-secondary) !important;
-  margin: 0 .5rem !important;
-  padding: .5rem !important;
-  width: 320px;
-  height: 60vh;
-  overflow-y: scroll;
-  flex: 0 0 auto;
-  overflow: visible;
-  display: flex;
-  flex-direction: column;
-}
-
-.board-column-header {
-  display: flex;
-  justify-content: space-between;
-}
-
-.board-label {
-  background: none !important;
-  line-height: 1.25 !important;
-}
-
-.board-column > .cards {
-  flex: 1;
-  display: flex;
-  flex-direction: column;
-  margin: 0 !important;
-  padding: 0 !important;
-
-  .card .meta > a.milestone {
-    color: #999999;
-  }
-}
-
-.board-column > .divider {
-  margin: 5px 0;
-}
-
-.board-column:first-child {
-  margin-left: auto !important;
-}
-
-.board-column:last-child {
-  margin-right: auto !important;
-}
-
-.board-card {
-  margin: 3px !important;
-  width: auto !important;
-  background-color: #fff;
-  border-radius: 5px;
-  cursor: pointer;
-}
-
-.board-card .header {
-  font-size: 1.1em !important;
-}
-
-.board-card .content {
-  padding: 8px 8px 5px !important;
-}
-
-.board-card .extra.content {
-  padding: 5px 8px !important;
-}
-
 td.blob-excerpt {
   background-color: #fafafa;
 }