Show repository size in repo home page and settings (#8940)

* feat: display repository size on repo home and settings

* refactor: move repo size up in setting page

options/locale/locale_en-US.ini

 owner = Owner
 repo_name = Repository Name
 repo_name_helper = Good repository names use short, memorable and unique keywords.
+repo_size = Repository Size 
 template = Template
 template_select = Select a template.
 template_helper = Make repository a template

templates/repo/settings/options.tmpl

 					<label for="repo_name">{{.i18n.Tr "repo.repo_name"}}</label>
 					<input id="repo_name" name="repo_name" value="{{.Repository.Name}}" data-repo-name="{{.Repository.Name}}" autofocus required>
 				</div>
+				<div class="inline field">
+					<label>{{.i18n.Tr "repo.repo_size"}}</label>
+					<span>{{SizeFmt .Repository.Size}}</span>
+				</div>
 				<div class="inline field">
 					<label>{{.i18n.Tr "repo.template"}}</label>
 					<div class="ui checkbox">

templates/repo/sub_menu.tmpl

 			<div class="item{{if .PageIsBranches}} active{{end}}">
 				<a class="ui" href="{{.RepoLink}}/branches/"><i class="octicon octicon-git-branch"></i> <b>{{.BranchesCount}}</b> {{.i18n.Tr (TrN .i18n.Lang .BranchesCount "repo.branch" "repo.branches") }}</a>
 			</div>
+			<div class="item">
+				<a class="ui" href="#"><i class="octicon octicon-database"></i> <b>{{SizeFmt .Repository.Size}}</b></a>
+			</div>
 		{{end}}
 	</div>
 </div>