[ADD][15.0] web_assets_manager

[fkantelberg]

By default Odoo website visitors download many large asset bundles which is bad for their performance. This module allows to customize the asset bundles to improve website performance. This can be useful for static webpages (other than portal sites and online shop) in particular.

It can improve the SEO ranking and performance a lot by reducing the total amount of CSS/JS downloaded by the client and reduce the size of unused code. But it can also brick the page/UI if not used wisely.