docs: improvements + additions to module docs (#9152)

- Split Module and Module Links to their own chapters
- Add new docs on db operations and transactions in modules, multiple services, links with custom columns, etc...
- Added a list of registered dependencies in a module container

www/apps/book/app/basics/modules-and-services/page.mdx

@@ -10,20 +10,12 @@ In this chapter, you’ll learn about modules, their main service, and how to cr
 
 A module is a package of reusable commerce or architectural functionalities. It's integrated as a building block in your Medusa application, without implications on the existing setup.
 
-You create a module to introduce custom features, extend existing ones, or integrate third-party services.
+A module has a service, which is a class that can connect to the database or third-party systems to provide custom features. The service's methods are then used by other resources, such as API routes.
 
 ---
 
 ## How to Create a Module?
 
-<Note title="Steps Summary">
-
-1. Create module's main service.
-2. Create module definition.
-3. Add module to Medusa's configurations.
-
-</Note>
-
 Modules are created in a sub-directory of `src/modules`.
 
 For example, create the directory `src/modules/hello`.
@@ -154,7 +146,8 @@ You’ll receive the following response:
 
 <Note title="Use modules when" type="success">
 
-- You're implementing a custom commerce feature. For example, you're implementing digital products.
+- You're adding new tables to the database, as explained in later chapters.
+- You're integrating a third-party system for commerce or architectural features.
 - You want to re-use your custom commerce functionalities across Medusa applications or use them in other environments, such as Edge functions and Next.js apps.
 
 </Note>