Refactor "org teams" page and help new users to "add member" to an org (#37051)

* Fix #22054
* Replace #34593, #27800
* And refactor legacy code, fix various problems

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Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>

templates/org/team/teams.tmpl

@@ -4,7 +4,8 @@
 	<div class="ui container">
 		{{template "base/alert" .}}
 		{{if .IsOrganizationOwner}}
-			<div class="flex-text-block tw-justify-end">
+			<div class="flex-text-block">
+				<div class="tw-flex-1">{{ctx.Locale.Tr "org.teams.manage_team_member_prompt"}}</div>
 				<a class="ui primary button" href="{{.OrgLink}}/teams/new">{{svg "octicon-plus"}} {{ctx.Locale.Tr "org.create_new_team"}}</a>
 			</div>
 			<div class="divider"></div>