Circuit Design for Current Measurement at High Voltage
Is the term Isolation Voltage in any way related to the Voltage Rating
  of the sense resistor of ACS722KMA?


A. Yes. The isolation barrier is inside the chip between the conductor and the hall effect sensor.
The voltage rating of the current channel is of no concern. Inside is 0.85 milli ohms. There will be no significant voltage.


  The Basic Isolation Working Voltage for ACS722KMA is stated 1097 Vrms in the datasheet, there is a little confusion if ACS722KMA be able to survive constant 2kVDC to 3kVDC


B. It is designed for continuous operation at 1097 Vrms, and can survive shorts bursts of higher voltages up to 4800 Vrms. (respecting the V/us limits)
You're probably going to have a hard time finding 3kV SiO2 isolator chips.
Optocouplers are the only way.


  I wasn't able to find current sense resistors with High Voltage Rating.


C. You don't need a high voltage rating for a shunt resistor. The 3 kV is common mode voltage for the shunt resistor.  You do however need to pay attention to the inductance of the resistor, since that might temporarily raise the voltage.


  If anyone would suggest any other component or technique


D. If it's only for indication you could perhaps use a digital method? A little micro sampling the shunt and sending UART frames over 1 optocoupler.
The more complicated way is to build a differential amplifier that allows for such high common mode. The concept as used in high voltage common mode probes.