Add OpenCyphal Node

[manforowicz]

This pull request:

• Enables the ESP32 to act as a simple OpenCyphal node if enabled in the web interface. This functionality is disabled by default. The OpenCyphal node broadcasts a heartbeat every second, and counts the number of heartbeats received.
• Adds collapsible descriptions to some of the setting fields in the web interface. This should make it easier to understand what those fields mean.
• Moves the CAN listening logic from socketcand_server.c to the new can_listener.c. This makes it possible for other tasks, such as in cyphal_node.c, to also listen to the CAN bus.
• Gets rid of the socketcand_translate_frame type, and instead uses the twai_message_t type everywhere.
• Adds some additional warning flags to GCC.
• Splits the .github workflow into build.yml and release.yml. build.yml uses the latest version of ESP-IDF, whereas release.yml uses a specified stable version of ESP-IDF.
• A few minor changes that simplify code, or improve behavior.