pxar: cleanup: move feature flags to src/pxar/flags.rs and omit CA_FORMAT prefix on all of them

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>

src/pxar.rs

@@ -50,6 +50,9 @@
 mod binary_search_tree;
 pub use binary_search_tree::*;
 
+pub mod flags;
+pub use flags::*;
+
 mod format_definition;
 pub use format_definition::*;