ASR not being generated for certain features

The following festures are supported by LFortran for basic usage and the AST is also generated, but ASR is not supported:

• If else Statements
• Loops (Tested for do loop)
• Function Calls
• Arithmetic Variable Assignments ( e.g. a = 10)
• Assignments like a = a + b + 2
• logical variables
• Print statements

NodeVisitors have not been implemented for these features for the creation of ASR