Update removed `platform.linux_distribution` funtion call in Python 3.8

[kushaldas]

Description

We are using platform.linux_distribution function in our metadata endpoint. But, this function was deprecated from Python3.5 and totally removed from Python 3.8.

Solution

We can directly read the /etc/lsb-release and /etc/os-release file as required.

[kushaldas]

#4768 is dependent on this.

[DrGFreeman]

@kushaldas and @eloquence, I can take care of this if it's OK with you.

[eloquence]

That would be awesome, thanks @DrGFreeman :)