feat: remove use of bitflags, flatten var modifiers

This removes a dependency, and makes the code cleaner. There is no
longer a possibility of having a xor range or base64 alphabet without
the corresponding flag, and the code is globally simpler.

Author: vthib

Cargo.lock

@@ -15,8 +15,5 @@ rust-version = "1.62"
 # Parsing library
 nom = "7.1"
 
-# packing multiple flags together
-bitflags = "1.3"
-
 # Proper error reporting on parsing
 codespan-reporting = "0.11"

boreal-parser/Cargo.toml

@@ -58,7 +58,8 @@ pub mod regex;
 pub use regex::Regex;
 mod rule;
 pub use rule::{
-    Metadata, Rule, VariableDeclaration, VariableDeclarationValue, VariableFlags, VariableModifiers,
+    Metadata, Rule, VariableDeclaration, VariableDeclarationValue, VariableModifierBase64,
+    VariableModifiers,
 };
 mod string;
 mod types;