feat: Add comprehensive guide to resource accounts with progressive examples

[l-monninger]

Summary

Provide a comprehensive guide for resource accounts in the Week 2 curriculum. This should be coupled with a Move project in examples/movement/resource_account.

Recommended Approach

1. Begin by drafting the examples.
   1. Begin with simplest possible usage of resource account you can imagine.
   2. Build up to resource account usage in examples/movement/mini_dex with a series of examples.
2. Write up content to cover examples.
3. Adjust content to include more generalized explanation of resource_accounts.