[ADD] account_xunnel: now online journal and periodicity to sync is visible in journal configuration

sycn are related fields, they don't need to be explicitly set or get,
for example field tax_cash_basis_journal_id on account module
https://github.com/odoo/odoo/blob/d34d6867f2ff9abdf303f12b3fb9b7fc20e709ab/addons/account/models/res_config_settings.py

We this, we pretend to dismiss the problem with those fields that being
cleaned after each production update.

Carmen Miranda authored Oct 29, 2019 and Olar Alca [Vauxoo] committed Oct 29, 2019

- Allow searching for emitter (emitter_partner_id) or total amount
(invoice_total_amount) by entering the keyword in the search field.
- Stamp Date field is now being stored and searchable with advanced
filters.

Carmen Miranda authored Oct 22, 2019 and Olar Alca [Vauxoo] committed Oct 22, 2019

- Change thumbnail date, from the sync date to the stamped date.
- Add Name's document and Total Amount inside the thumbnail under the title.
- Emitter name field and total computed field are being stored.
- Add help for the fields in the model "ir.attachment"
- Add translations for the help and name of the fields.

[FIX] invoice_xunnel: Display attachments were failing at changes to the next attach, because they were filtered wrongly

	A new wizard was added to change the last syncrhonization
	with xunnel even if the user has only accountant user permision.

	This wizard can be open in the accountant dashboard in the
	journal options.

	The xml downloaded from Xunnel now have a fancy preview if you click
	in its icon in the documents module. Also, if an attribute or its value
	its clicked, their value will be copy to the clipboard.

Olar Alca [Vauxoo] authored Mar 26, 2019 and Javier Vega committed Apr 01, 2019

	supplier invoice.
[IMP] invoice_xunnel: Changed tag for sync instead of xunnel/xunnel.

	The attachment downloaded from Xunnel now can be found in
	the Xunnel folder within the Documents app and be converted
	into invoices.

	Also, now the action of synchronizing attachment can fail
	in someones and still continue with the job. The message
	also was improved to show how many errors and success
	happened.