IDE: Allow environment variable override in ThirdPartyPath, and use it also for matiec.

IDE: re-use eRPC URI definitions in connector factory.

Preparing for serial and US eRPC connection.

Cosmetic changes

IDE: refactor discovery panel / zeroconf

Bundle ZeroConf listener and interfaces changes monitor into separate module.
Prepare to extend with USB device browsing.

IDE: refactor ERPC URI editor, add serial and USB URI types

python runtime: update ServicePublisher to current Zeroconf API

eRPC: Backward compatibility with runtime versions missing GetVersions extended call.

eRPC: Version bump

python_runtime: fix ExtendedCall register/unregistering.

eRPC: Server closes connection on exception to prevent client to block until timeout when it happens.

Add ExtendedCall to PLCObject as a replacement of RemoteExec and reflect it in eRPC interface.

ExtendedCall is a generic remote procedure call that runtime code can register to and that IDE extensions can call.
For example a fieldbus extension can use ExtendedCall to browse the fieldbus devices connected to the runtime.

Removed dependency in requirements.txt.

TESTS: Update Matiec revision in GH workflow

MQTT: update test project to reflect latest changes

SVGHMI update generated XSLT

SVGHMI: remove widgets deprecated since long

SVGHMI: add ForEach widget example

SVGHMI: Extend ForEach widget to expose range, position and size in a way comparable with ScrollBar widget.

SVGHMI: code cleanup

MQTT: Add status global variable MQTT_STATUS_n, one per MQTT client

MQTT: strip unsupported types from type choice dropdown, better wrong type detection in build.

MQTT: remove debug prints

MQTT: add JSON fixed size 1D array support. WIP. Parsing array still broken.

MQTT: do not convert to UPPERCASE json keys.

MQTT: added support for strings in JSON payload only.

MQTT: remove accidentally committed debug printfs + cosmetic

MQTT: fix invocation of json_scanf (use pointers, not values...)

MQTT: fix bisection failing when topics start with same substring.