Context menu for project (bug#69566)

Context menu for project (bug#69566)

* lisp/menu-bar.el (menu-bar-project-item): New variable from
'project-menu-entry'.
(menu-bar-tools-menu): Use 'menu-bar-project-item'.

* lisp/mouse.el (context-menu-functions): Add
'context-menu-project' to choice.
(context-menu-project): New function.

* lisp/progmodes/project.el (project-menu-entry): Remove variable.
(project-mode-line-map): Use 'menu-bar-project-item' instead of
'project-menu-entry'.

(cherry picked from commit f3deaa117acfc975be3edbe8461b18fc29b4adf0)