Documentation: migrate apps/logging doc

Documentation/applications/logging/embedlog/index.rst

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+================
+Embedlog Library
+================
+
+Highly configurable logger for embedded devices. Documentation and
+more info available on: https://embedlog.bofc.pl

Documentation/applications/logging/index.rst

@@ -1,3 +1,10 @@
 =================
 Logging Utilities
 =================
+
+.. toctree::
+   :glob:
+   :maxdepth: 3
+   :titlesonly:
+
+   */*

Documentation/applications/logging/nxscope/index.rst

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+===============
+NxScope Library
+===============
+
+This library provides real-time data logging functionality for NuttX.
+
+The principle of action is to accumulate data gathered in virtual channels
+and periodically send buffered data through a dedicated interface packed
+with a custom protocol.
+
+Supported features:
+
+- up to 255 channels possible
+- support for standard data types and user-specific data (``enum nxscope_sample_dtype_e``)
+- support for vector data or point data
+- support for character-based channels (text messages)
+- support for channel metadata - can be used to enumerate samples or timestamp
+- stream buffer overflow detection (``NXSCOPE_STREAM_FLAGS_OVERFLOW``)
+- remote control with commands (``enum nxscope_hdr_id_e``)
+- protocol and interface implementation can be different for control commands and stream data
+- (optional) support for user-specific commands (``NXSCOPE_HDRID_USER`` and ``struct nxscope_callbacks_s``)
+- (optional) support for samples divider (``CONFIG_LOGGING_NXSCOPE_DIVIDER``)
+- (optional) support for ACK frames (``CONFIG_LOGGING_NXSCOPE_ACKFRAMES``)
+- (optional) support for user-defined types (``CONFIG_LOGGING_NXSCOPE_USERTYPES``)
+- (optional) support for non-buffered critical channels (``CONFIG_LOGGING_NXSCOPE_CRICHANNELS``)
+
+A custom interface and a custom protocol can be implemented with
+``struct nxscope_intf_s`` and ``struct nxscope_proto_s`` structures.
+
+Supported interfaces:
+
+1. a serial port: ``logging/nxscope/nxscope_iser.c``
+2. a dummy interface for debug purposes: ``logging/nxscope/nxscope_idummy.c``
+
+A default serial protocol is implemented in ``apps/logging/nxscope/nxscope_pser.c``
+It just packs NxScope data into simple frames with a CRC-16 checksum.
+
+External tools
+--------------
+
+- `Nxslib <https://github.com/railab/nxslib>`_ - a Python (3.10+) client library for NxScope devices,
+- `Nxscli <https://github.com/railab/nxscli>`_ - a Python (3.10+) command-line interface for NxScope,
+  supporting data capture and visualization