rialto: Use PageTable from pvmfw through vmbase

Extract the file to vmbase.

Use it in Rialto to replace the existing PT manipulation cofiguration.

Bug: 282928116
Test: atest rialto_test
Change-Id: If9aaa30fb60781cebc82cf34ebe94a9a580beace
diff --git a/vmbase/src/memory/mod.rs b/vmbase/src/memory/mod.rs
index c4990f2..149fd18 100644
--- a/vmbase/src/memory/mod.rs
+++ b/vmbase/src/memory/mod.rs
@@ -15,5 +15,7 @@
 //! Memory management.
 
 mod dbm;
+mod page_table;
 
 pub use dbm::set_dbm_enabled;
+pub use page_table::{PageTable, MMIO_LAZY_MAP_FLAG};