[FIX] account: several fixes on the new bank statement reconciliation widget

addons/account/account.py

addons/account/account_bank_statement.py

addons/account/account_invoice.py

addons/account/account_move_line.py

addons/account/account_view.xml

addons/account/demo/account_bank_statement.xml

addons/account/demo/account_invoice_demo.xml

addons/account/res_config.py

addons/account/res_config_view.xml

.../static/src/css/account_bank_statement_reconciliation.css

...static/src/css/account_bank_statement_reconciliation.scss

...atic/src/js/account_tour_bank_statement_reconciliation.js

addons/account/static/src/js/account_widgets.js

.../static/src/xml/account_bank_statement_reconciliation.xml

addons/account/tests/__init__.py

.../account/tests/test_bank_stmt_reconciliation_widget_ui.py

addons/account/tests/test_reconciliation.py

addons/account/views/account.xml

addons/account_voucher/account_voucher.py

addons/account_voucher/account_voucher_view.xml