[IMP] IoT: clear printer cache

[jero-odoo]

Docs task: https://www.odoo.com/mail/view?model=project.task&res_id=4014860&access_token=f97d0b66-1081-4607-b330-fbe291abe40a

Updating IoT printer doc with "Clear Selected devices" feature. Also made updates to screenshots and small updates to wording/grammar.

[robodoo]

[jero-odoo]

@pabr-odoo this is ready for peer review. Thanks!

[jero-odoo]

Hey @ksc-odoo this is ready for final review. Thanks!

[jero-odoo]

Thanks KC! @samueljlieber this is ready for tech review. Thanks!