[ADD] dav_account: create addon to connect Odoo to a DAV server

Users can add several DAV servers to their profile preferences.

dav_account/models/dav_server.py

@@ -0,0 +1,33 @@
+import caldav
+from odoo import api, fields, models
+
+
+class DavServer(models.Model):
+    _name = "dav.server"
+    _description = "Dav server"
+
+    name = fields.Char('name', required=True, copy=True)
+    url = fields.Char('Server url', required=True, copy=True)
+    username = fields.Char('Username', required=True, copy=True)
+    password = fields.Char('Password', required=True, copy=False)
+    user_id = fields.Many2one('res.users', string='User', required=True, copy=True, ondelete="cascade")
+    status = fields.Char(compute='_compute_status', string='Status', store=True)
+    
+    @api.depends("url", "username", "password")
+    def _compute_status(self):
+        try:
+            self.get_principal()
+            self.write({"status": "OK"})
+        except:
+            self.write({"status": "KO"})
+
+    def get_principal(self):
+        ## When using the caldav library, we start with initiating a
+        ## DAVClient object, which should contain connection details and credentials.
+        ## Initiating the object does not cause any requests to the server, so this
+        ## will not break even if caldav url is set to example.com
+        client = caldav.DAVClient(url=self.url, username=self.username, password=self.password)
+        ## principal object will cause communication with the server.
+        principal = client.principal()
+        return principal
+