Add user/organization code search (#19977)

Fixes #19925 

Screenshots:

![attels](https://user-images.githubusercontent.com/165205/173864718-fe789429-55bc-4cad-808c-9f02f335cddf.png)

templates/user/code.tmpl

@@ -0,0 +1,25 @@
+{{template "base/head" .}}
+<div class="page-content repository code-search">
+	{{template "user/overview/header" .}}
+	<div class="ui container">
+		{{template "code/searchform" .}}
+		<div class="ui divider"></div>
+		<div class="ui user list">
+			{{if .CodeIndexerUnavailable }}
+				<div class="ui error message">
+					<p>{{$.locale.Tr "explore.code_search_unavailable"}}</p>
+				</div>
+			{{else if .SearchResults}}
+				<h3>
+					{{.locale.Tr "explore.code_search_results" (.Keyword|Escape) | Str2html }}
+				</h3>
+				{{template "code/searchresults" .}}
+			{{else if .Keyword}}
+				<div>{{$.locale.Tr "explore.code_no_results"}}</div>
+			{{end}}
+		</div>
+
+		{{template "base/paginate" .}}
+	</div>
+</div>
+{{template "base/footer" .}}