Switch from macros to blocks for navigation menus

This affects the user and notifications menus. It happens for two reasons:
- the only argument passed to the macros was current_user, which is always available
- we want to enable overriding and adding items to the menus via extensions

At the moment only the user menu takes advantage of the base template, since the blender-cloud extension makes use of it, while notifications.pug does not need it yet.

src/templates/menus/notifications.pug

@@ -0,0 +1,23 @@
+| {% if current_user.is_authenticated %}
+
+li.nav-notifications
+	a.navbar-item#notifications-toggle(
+	title="Notifications",
+	data-toggle="tooltip",
+	data-placement="bottom")
+		i.pi-notifications-none.nav-notifications-icon
+		span#notifications-count
+			span
+		.flyout-hat
+
+	#notifications.flyout.notifications
+		.flyout-content
+			span.flyout-title Notifications
+			a#notifications-markallread(
+			title="Mark All as Read",
+			href="/notifications/read-all")
+				| Mark All as Read
+
+			| {% include '_notifications.html' %}
+
+| {% endif %}

src/templates/menus/user.pug

@@ -0,0 +1 @@
+| {% extends 'menus/user_base.html' %}

src/templates/menus/user_base.pug

@@ -0,0 +1,66 @@
+| {% block menu_body %}
+| {% if current_user.is_authenticated %}
+
+li(class="dropdown")
+	| {% block menu_avatar %}
+	a.navbar-item.dropdown-toggle(href="#", data-toggle="dropdown", title="{{ current_user.email }}")
+		img.gravatar(
+		src="{{ current_user.gravatar }}",
+		alt="Avatar")
+	| {% endblock menu_avatar %}
+
+	ul.dropdown-menu
+		| {% if not current_user.has_role('protected') %}
+		| {% block menu_list %}
+		li
+			a.navbar-item(
+			href="{{ url_for('projects.home_project') }}"
+			title="Home")
+				i.pi-home
+				| Home
+
+		li
+			a.navbar-item(
+			href="{{ url_for('projects.index') }}"
+			title="My Projects")
+				i.pi-star
+				| My Projects
+
+		| {% if current_user.has_organizations() %}
+		li
+			a.navbar-item(
+			href="{{ url_for('pillar.web.organizations.index') }}"
+			title="My Organizations")
+				i.pi-users
+				| My Organizations
+		| {% endif %}
+
+		li
+			a.navbar-item(
+			href="{{ url_for('settings.profile') }}"
+			title="Settings")
+				i.pi-cog
+				| Settings
+
+		| {% endblock menu_list %}
+
+		li.divider(role="separator")
+		| {% endif %}
+
+		li
+			a.navbar-item(
+			href="{{ url_for('users.logout') }}")
+				i.pi-log-out(title="Log Out")
+				| Log out
+			a.navbar-item.subitem(
+			href="{{ url_for('users.switch') }}")
+				i.pi-blank
+				| Not {{ current_user.full_name }}?
+
+| {% else %}
+
+li.nav-item-sign-in
+	a.navbar-item(href="{{ url_for('users.login') }}")
+		| Log in
+| {% endif %}
+| {% endblock menu_body %}