[ADD] project_timebox: create addon to estimate task effort

Adds fields to estimate the min and max time needed to solve a task.

Task: [JOI-13](https://justodooit.fr/mail/view?model=project.task&res_id=13&access_token=cca0b860-25d1-472d-9da1-76f68b01a932)

project_timebox/__manifest__.py

@@ -0,0 +1,92 @@
+# Copyright 2022 Stéphan Sainléger (Elabore)
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+{
+    "name": "project_timebox",
+    "version": "12.0.1.0.0",
+    "author": "Elabore",
+    "website": "https://elabore.coop",
+    "maintainer": "Stéphan Sainléger",
+    "license": "AGPL-3",
+    "category": "Project",
+    "summary": "Add timebox field in tasks to estimate resolution effort.",
+    "description": """
+   :image: https://img.shields.io/badge/licence-AGPL--3-blue.svg
+   :target: http://www.gnu.org/licenses/agpl-3.0-standalone.html
+   :alt: License: AGPL-3
+===============
+project_timebox
+===============
+
+Add timebox field in tasks to estimate resolution effort.
+
+Installation
+============
+
+Use Odoo normal module installation procedure to install ``project_timebox``.
+To configure the timeboxes, go to Project > Configuration > Timeboxes
+
+Known issues / Roadmap
+======================
+
+None yet.
+
+Bug Tracker
+===========
+
+Bugs are tracked on `our issues website <https://github.com/elabore-coop/project-tools/issues>`_. In case of
+trouble, please check there if your issue has already been
+reported. If you spotted it first, help us smashing it by providing a
+detailed and welcomed feedback.
+
+Credits
+=======
+
+Contributors
+------------
+
+* Stéphan Sainléger (https://github.com/stephansainleger)
+* Nicolas Jeudy (https://github.com/njeudy)
+
+Funders
+-------
+
+The development of this module has been financially supported by:
+* Elabore (https://elabore.coop)
+* Mycéliandre (https://myceliandre.fr)
+* Lokavaluto (https://lokavaluto.fr)
+
+
+Maintainer
+----------
+
+This module is maintained by Elabore.
+
+""",
+    # any module necessary for this one to work correctly
+    "depends": [
+        "base",
+        "project",
+    ],
+    "qweb": [
+        # "static/src/xml/*.xml",
+    ],
+    "external_dependencies": {
+        "python": [],
+    },
+    # always loaded
+    "data": [
+        "security/ir.model.access.csv",
+        "views/project_task.xml",
+        "views/timebox.xml",
+    ],
+    # only loaded in demonstration mode
+    "demo": [],
+    "js": [],
+    "css": [],
+    "installable": True,
+    # Install this module automatically if all dependency have been previously
+    # and independently installed.  Used for synergetic or glue modules.
+    "auto_install": False,
+    "application": False,
+}