Add support for managing attachments

Add a new manager for attachment records (`ir.attachment`) in Odoo.

These are intended to be used for uploading/downloading attachments to/from invoices.
Invoice attachments will then be attached to invoice emails sent out to customers.

The contents of the attachments won't be fetched when querying them from Odoo by default;
instead it is intended that the separate `download` method be used to download the attachment
contents separately. An `upload` method is also available, to provide an easier to use interface
for uploading attachments.

Author: Callum Dickinson

_typos.toml

@@ -0,0 +1,2 @@
+[default.extend-words]
+datas = "datas"

changelog.d/7.added.md

@@ -0,0 +1 @@
+Add support for managing attachments

docs/managers/account-move.md

@@ -265,7 +265,7 @@ Values:
 * ``reversed`` - Reversed
 * ``invoicing_legacy`` - Invoicing App Legacy
 
-### state
+### `state`
 
 ```python
 state: Literal["draft", "posted", "cancel"]