feat: Implement compiler and virtual machine for Fig language

- Added Compiler class with methods for compiling programs, statements, and expressions.
- Introduced Proto structure to hold compiled bytecode and constants.
- Implemented expression compilation including literals, identifiers, and infix expressions.
- Developed statement compilation for variable declarations and expression statements.
- Created a VM class to execute compiled bytecode with support for arithmetic and comparison operations.
- Added Object and Value classes for handling different data types and memory management.
- Implemented String and Struct objects for enhanced data representation.
- Established a parser for parsing variable declarations and statements.
- Included tests for the VM and object representations.

src/Error/Error.cpp

@@ -52,7 +52,10 @@ namespace Fig
             case ExpectedExpression: return "ExpectedExpression";
             case SyntaxError: return "SyntaxError";
 
-            // default: return "Some one forgot to add case to `ErrorTypeToString`";
+            case RedeclarationError: return "RedeclarationError";
+            case UseUndeclaredIdentifier: return "UseUndeclaredIdentifier";
+            case NotAnLvalue: return "NotAnLvalue";
+                // default: return "Some one forgot to add case to `ErrorTypeToString`";
         }
     }