Java program to convert temperature in Fahrenheit to temperature in Celsius

[AK271]

Description

Java program that takes temperature in Fahrenheit as input and converts it to temperature in Celsius.

Fixes #470

Type of change

Please delete options that are not relevant

• [x] New feature (non-breaking change which adds functionality)
• [x] This change requires a documentation update

Checklist:

• [x] I have read the contribution guidelines before making this PR.
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented in my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation (Language folder or any other readme instructed to)
• [x] My changes generates no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works