feat: implement class navigation in large class definitions

[AlexTheWizardL]

This pull request cover changes for implementing class navigation in large class definitions

Here is logical groups that was created:

CashCtrlClient

1. Constructors
2. Helper Methods
3. API Requests
4. File Operations
5. Tax Rates
6. Accounts
7. Categories
8. Ledger

---

CachedCashCtrlClient

1. Constructors
2. Helper Methods
3. API Requests
4. File Operations
5. Tax Rates
6. Accounts
7. Categories
8. Ledger
9. Cache Invalidation

@lasuk Please review the changes and provide feedback or approval for merging.

[lasuk]

Thanks a lot! This makes navigating the code base much easier.

I've added two commits d484bcd and 3637acd to further clarify sections. Please shout if you disagree..

I've fixed a mistake introduced by ChatGPT in 973fb91:

• Removed methods that were not part of the original CachedCashCtrl client.
• Please be careful when re-factoring with ChatGPT. It is more prudent to copy-paste code blocks manually because we can then be sure that the code is unchanged.