Require type attribute on button elements

[AndreaBarbasso]

Is your feature request related to a problem? Please describe.

We have some components that include buttons without an explicit type attribute (e.g. ds-entity-dropdown). This can cause issues when such components are included in a <form>, since the default type for a button is - counterintuitively - submit, and not button.

Describe the solution you'd like

I think the best approach to overcome this potential issue is to include a linting rule (e.g. https://html-eslint.org/docs/rules/require-button-type) to require an explicit button type.