[Feature]: create string_comp and string_comp_case for comparing two string

[mainak55512]

1. string_comp
   Signature: bool string_comp(String *s1, String *s2)
   This will compare strings case-insensitive

2. string_comp_case
   Signature: bool string_comp_case(String *s1, String *s2)
   This will compare strings case-sensitive

[Forsaken-16]

hi i solved this and created pull requests for these 2 functions