Color and Style enhancements (#21784, #21799) (#21868)

Backport #21784
Backport #21799

These PRs provide tweaks and simplification to the less/css selectors, simplifying text color selectors and tweak arc-green colors with a follow-up to adjust the timeline 

See the original PRs for more details

templates/repo/issue/view_content.tmpl

@@ -30,7 +30,7 @@
 					<div class="ui top attached header comment-header df ac sb">
 						<div class="comment-header-left df ac">
 							{{if .Issue.OriginalAuthor}}
-								<span class="text black">
+								<span class="text black bold">
 									{{svg (MigrationIcon .Repository.GetOriginalURLHostname)}}
 									{{.Issue.OriginalAuthor}}
 								</span>
@@ -45,7 +45,7 @@
 									{{avatar .Issue.Poster}}
 								</a>
 								<span class="text grey">
-									<a class="author"{{if gt .Issue.Poster.ID 0}} href="{{.Issue.Poster.HomeLink}}"{{end}}>{{.Issue.Poster.GetDisplayName}}</a>
+									{{template "shared/user/authorlink" .Issue.Poster}}
 									{{.locale.Tr "repo.issues.commented_at" (.Issue.HashTag|Escape) $createdStr | Safe}}
 								</span>
 							{{end}}