[Feature]: Implement data validity flag and last communication timestamp between evok and end devices

[tomashora]

Describe the feature

The idea behind this feature requestr is to provide two additional values in each value getter and also setter:

• Value last communication timestamp - provides information when the value has been succesfully communicated (applies for both read and write functions)
• Value communication flag - this could be a dictionary possible states (ok, timeout, error,...)

Use case

Currently users have to get values using value getters and in case of Modbus slave chceck for the value of last_comm within Read modbus_slave function to find out if the value is valid and can be used in their application or another action shoudl be taken, which is not ideal.

Alternatives Considered

No response

Additional context

No response