Introduce filtered list view model

We're going to start supporting filtering of list views

pkg/gui/controllers/search_controller.go

@@ -0,0 +1,48 @@
+package controllers
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/gui/types"
+)
+
+type SearchControllerFactory struct {
+	c *ControllerCommon
+}
+
+func NewSearchControllerFactory(c *ControllerCommon) *SearchControllerFactory {
+	return &SearchControllerFactory{
+		c: c,
+	}
+}
+
+func (self *SearchControllerFactory) Create(context types.ISearchableContext) *SearchController {
+	return &SearchController{
+		baseController: baseController{},
+		c:              self.c,
+		context:        context,
+	}
+}
+
+type SearchController struct {
+	baseController
+	c *ControllerCommon
+
+	context types.ISearchableContext
+}
+
+func (self *SearchController) Context() types.Context {
+	return self.context
+}
+
+func (self *SearchController) GetKeybindings(opts types.KeybindingsOpts) []*types.Binding {
+	return []*types.Binding{
+		{
+			Key:         opts.GetKey(opts.Config.Universal.StartSearch),
+			Handler:     self.OpenSearchPrompt,
+			Description: self.c.Tr.StartSearch,
+		},
+	}
+}
+
+func (self *SearchController) OpenSearchPrompt() error {
+	return self.c.Helpers().Search.OpenSearchPrompt(self.context)
+}