logging: rpc: get rid of global output buffer

[Damian-Nordic]

1. Remove the global log output and output buffer from the nRF RPC logging backend.
2. Add helper functions to format a log message into a buffer, and align the backend to use these helpers.

Thanks to these changes, it is possible to format log messages from multiple threads, which will be utilized in an upcoming PR. Additionally, even a large message can now be sent in a single RPC event.

[NordicBuilder]

CI Information

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Build number: 1

Inputs:

Sources:

sdk-nrf: PR head: 32ad6e7014281394d83e87aa79ef547eb4fe5427

more details

sdk-nrf:

PR head: 32ad6e7014281394d83e87aa79ef547eb4fe5427
merge base: b4851abf9b0a48c77b133768b1b7012ab15c09dd
target head (main): 52d64989e8d7f4b4b7b3cefeca940d9f2a8be081
Diff

Github labels

Enabled	Name	Description
	ci-disabled	Disable the ci execution
	ci-all-test	Run all of ci, no test spec filtering will be done
	ci-force-downstream	Force execution of downstream even if twister fails
	ci-run-twister	Force run twister
	ci-run-zephyr-twister	Force run zephyr twister

List of changed files detected by CI (2)

subsys
│  ├── logging
│  │  ├── Kconfig
│  │  │ log_backend_rpc.c

Outputs:

Toolchain

Version: b77d8c1312
Build docker image: docker-dtr.nordicsemi.no/sw-production/ncs-build:b77d8c1312_912848a074

Test Spec & Results: ✅ Success; ❌ Failure; 🟠 Queued; 🟡 Progress; ◻️ Skipped; ⚠️ Quarantine

• ◻️ Toolchain - Skipped: existing toolchain is used
• ✅ Build twister
  • sdk-nrf test count: 47
• ✅ Integration tests

Disabled integration tests

• • desktop52_verification
  • doc-internal
  • test_ble_nrf_config
  • test-fw-nrfconnect-apps
  • test-fw-nrfconnect-ble_mesh
  • test-fw-nrfconnect-ble_samples
  • test-fw-nrfconnect-boot
  • test-fw-nrfconnect-chip
  • test-fw-nrfconnect-fem
  • test-fw-nrfconnect-nfc
  • test-fw-nrfconnect-nrf-iot_libmodem-nrf
  • test-fw-nrfconnect-nrf-iot_lwm2m
  • test-fw-nrfconnect-nrf-iot_mosh
  • test-fw-nrfconnect-nrf-iot_nrf_provisioning
  • test-fw-nrfconnect-nrf-iot_positioning
  • test-fw-nrfconnect-nrf-iot_samples
  • test-fw-nrfconnect-nrf-iot_serial_lte_modem
  • test-fw-nrfconnect-nrf-iot_thingy91
  • test-fw-nrfconnect-nrf-iot_zephyr_lwm2m
  • test-fw-nrfconnect-nrf_crypto
  • test-fw-nrfconnect-ps
  • test-fw-nrfconnect-rpc
  • test-fw-nrfconnect-rs
  • test-fw-nrfconnect-tfm
  • test-fw-nrfconnect-thread
  • test-fw-nrfconnect-zigbee
  • test-low-level
  • test-sdk-audio
  • test-sdk-dfu
  • test-sdk-find-my
  • test-sdk-mcuboot
  • test-sdk-pmic-samples
  • test-sdk-sidewalk
  • test-sdk-wifi
  • test-secdom-samples-public

Note: This message is automatically posted and updated by the CI

[NordicBuilder]

You can find the documentation preview for this PR at this link. It will be updated about 10 minutes after the documentation build succeeds.

Note: This comment is automatically posted by the Documentation Publish GitHub Action.

[Damian-Nordic]

@nordicjm I could use your review :)