[rtl872x] fix sleep PSRAM

[avtolstoy]

Description

1. Application thread stack is statically allocated from SRAM
2. Heap allocations prefer SRAM first now, and then PSRAM, previously it was the opposite
3. ^^ Makes System thread also have stack on SRAM, not PSRAM
4. Minor: system thread has a distinct thread name vs default active_object
5. PSRAM suspend/resume procedure issues resolved
6. Stub out direct flash read from BLE SDK code (we do not allow direct flash access without our HAL functions)

Steps to Test

• wiring/watchdog
• runner/mailbox with System.reset() replaced with System.sleep()

Example App

N/A

References

N/A

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Completeness

• User is totes amazing for contributing!
• Contributor has signed CLA (Info here)
• Problem and Solution clearly stated
• Run unit/integration/application tests on device
• Added documentation
• Added to CHANGELOG.md after merging (add links to docs and issues)