This change renames several internal JavaScript models so their names align with related server-side names. It helps keep the codebase clearer and easier to maintain, with no expected change to day-to-day user workflows.

Enterprise counter-part.

Part of task-3605717

https://github.com/odoo/odoo/pull/182364

This update simplifies how Odoo determines its internal root path by treating it as a runtime value rather than a configurable option. It supports a broader technical cleanup and should not change how users work with the system.

This commit is part of a larger refactor, see associated PR.

While `root_path` was defined as an option, in reality it cannot be set nor via the CLI, nor via the config file. Its value is fully defined at runtime and isn't modified anywhere.

Companion of https://github.com/odoo/odoo/pull/126099