In Colombia, all POS Sales/Returns must be supported by an Electronic Document. Currently, the only way to connect the DIAN EDI and POS flows is to manage invoices directly in the Accounting App. This pr adds the possibility to generate and send the electronic documents directly to DIAN without leaving the POS store.

This pr will not create intermediate invoices/credit notes that are supposed to be sent to DIAN, instead we adapted the already existing ubl-generation implementation (in `l10n_co_dian`) to be able to generate the correct files using data from `pos.order` models (implementation can be found in `models/account_edi_xml_ubl_dian.py`). During this process we created some 'common' functions that generate data for the ubl file independent of what model is used (`account.move` or `pos.order`), these common functions are a first step for the future refactoring of the ubl models. An important thing to note here is that the common functions are only used for the pos orders, generating documents for invoices is still done using the original implementation.

Another important feature of this implementation is the possibility to share a single sequence, defined on the journal, between pos orders and account moves. This was implemented because in Colombia (and other latam countries) the sequence gets assigned to a company by the government, and can therefore be expensive. Important to note is that sharing a sequence is only possible if the company has never sent documents to DIAN before (~ no existing edi documents).

task-4038651