Update HW reqs for Full node (MystenLabs#11370)

## Description 

Describe the changes or additions included in this PR.

## Test Plan 

How did you test the new or updated feature?

---
If your changes are not user-facing and not a breaking change, you can
skip the following section. Otherwise, please indicate what changed, and
then add to the Release Notes section as highlighted during the release
process.

### Type of Change (Check all that apply)

- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

doc/src/build/fullnode.md

@@ -45,7 +45,7 @@ Follow the instructions here to run your own Sui Full.
 
 Suggested minimum hardware to run a Sui Full node:
 
-- CPUs: 10 physical cores / 20 vCPUs
+- CPUs: 8 physical cores / 16 vCPUs
 - RAM: 128 GB
 - Storage (SSD): 2 TB NVMe drive
 

doc/src/learn/exchange-integration-guide.md

@@ -9,7 +9,7 @@ This topic describes how to integrate SUI, the token native to the Sui network,
 The requirements to configure a SUI integration include:
  * A Sui Full node. You can operate your own Sui Full node or use a Full node from a node operator.
  * Suggested hardware requirements to run a Sui Full node:
-    * CPU: 10 physical cores / 20 vCPUs
+    * CPU: 8 physical cores / 16 vCPUs
     * RAM: 128 GB
     * Storage (SSD): 2 TB NVMe drive