Remake of the parser

[thi8v]

With the new log system, I'm remaking the parser, because the old one is old and crapy and I want to change the grammar of the language so kill two birds with one stone.

TODO:

• new log / error system -> Improve the error handling in the compiler #55
  • allow errors on multiple lines
  • improve note and help to be able to point to code
  • in the parse_parenthesized_expr, add a note about the expected closing partenthesis to point to the opening one.
• package clause
• import declaration
• function top level declaration
• extern function tl. decl
• var & const-var top level declaration
• types
  • Primitive Types
  • Pointer & const pointer
• expression
  • int literal
  • char literal
  • string literal
  • boolean literal
  • identifier expr
  • call expr
  • undefined expr -> see unresolved questions
  • parenthesized expr
  • member access
  • binary a + b -> Operator precedence parser
  • unary -a, !a, &a, and a.*
  • if-else expr -> a if predicate else b
  • make Block stmt an expression
• statements
  • var & const-var declaration
  • if-else
  • block stmt
  • return
  • while
  • labeled stmts
    • while
    • block
  • break
  • continue
  • expr stmt
  • short var declaration ? -> $IdentifierList := $ExprList
  • assignment
  • post & pre -fix increment and decrement i++, i--, ++i and --i -> will potentialy be done later, the question hasn't yet been resolved
• move operators related stuff in zom_common::token in its own module
• add tests -> Adding Tests #6
  • in the parser
  • in the lexer
  • in the log crate

Unresolved questions

• Is it still relevant to make the undefined expression ? With the new path Zom is taking, the path of simplicity, should instead allow variable declaration with the expr optional : const test: u32?
  -> We allow to define a variable without initializing its expression, and we remove the 'undefined' expression, and keyword.
• Should we make := its own operator?
  -> Will not be answered here / now.
• If we make the postfix increment / decrement we couldn't make the array concatenation operator like in Zig, a ++ b, what do we do?
  -> Will not be answered here / now.