landing-zone-v2 readme doc update

**Is your feature request related to a problem? Please describe.**
The landing-zone-v2 implementation doesn't include all the sub packages (like logging, vpc, billing export and so on) to have the complete landing zone deployment.

**Describe the solution you'd like**
Is there any estimated time when we can expect the readme file updated to include other solutions(sub-packages) to have a complete landing zone v2 deployment.