Propagate context and ensure git commands run in request context (#17868)

This PR continues the work in #17125 by progressively ensuring that git
commands run within the request context.

This now means that the if there is a git repo already open in the context it will be used instead of reopening it.

Signed-off-by: Andrew Thornton <art27@cantab.net>

templates/repo/settings/options.tmpl

@@ -91,7 +91,7 @@
 					{{if .Repository.IsMirror}}
 					<tbody>
 						<tr>
-							<td>{{(MirrorRemoteAddress .Mirror).Address}}</td>
+							<td>{{(MirrorRemoteAddress $.Context .Mirror).Address}}</td>
 							<td>{{$.i18n.Tr "repo.settings.mirror_settings.direction.pull"}}</td>
 							<td>{{.Mirror.UpdatedUnix.AsTime}}</td>
 							<td class="right aligned">
@@ -119,7 +119,7 @@
 										<label for="interval">{{.i18n.Tr "repo.mirror_interval"}}</label>
 										<input id="interval" name="interval" value="{{.MirrorInterval}}">
 									</div>
-									{{$address := MirrorRemoteAddress .Mirror}}
+									{{$address := MirrorRemoteAddress $.Context .Mirror}}
 									<div class="field {{if .Err_MirrorAddress}}error{{end}}">
 										<label for="mirror_address">{{.i18n.Tr "repo.mirror_address"}}</label>
 										<input id="mirror_address" name="mirror_address" value="{{$address.Address}}" required>
@@ -168,7 +168,7 @@
 					<tbody>
 						{{range .PushMirrors}}
 						<tr>
-							{{$address := MirrorRemoteAddress .}}
+							{{$address := MirrorRemoteAddress $.Context .}}
 							<td>{{$address.Address}}</td>
 							<td>{{$.i18n.Tr "repo.settings.mirror_settings.direction.push"}}</td>
 							<td>{{if .LastUpdateUnix}}{{.LastUpdateUnix.AsTime}}{{else}}{{$.i18n.Tr "never"}}{{end}} {{if .LastError}}<div class="ui red label tooltip" data-content="{{.LastError}}">{{$.i18n.Tr "error"}}</div>{{end}}</td>