Merge 'Beginnings of AUTOVACUUM' from Zaid Humayun

This PR adds the beginnings of
[AUTOVACUUM](https://www.sqlite.org/lang_vacuum.html) to Limbo. It adds
a feature flag called `omit_autovacuum` which is analogous to
`SQLITE_OMIT_AUTOVACUUM`. It is off by default, same as SQLite.
It introduces the concept of [pointer map pages](https://www.sqlite.org/
fileformat.html#pointer_map_or_ptrmap_pages) which are reverse index
pages used to map pages to their parents. This is used to swap pages
(when a table is deleted for instance) to keep root pages clustered at
the beginning of the file. It's also used while creating a table to
ensure that root pages are clustered at the beginning (although, this
isn't completely implemented yet)
Finally, it also adds a couple of missing instructions like `Int64` that
are required for `PRAGMA` commands related to `auto_vacuum` settings
<img width="1512" alt="Screenshot 2025-05-28 at 8 47 51 PM"
src="https://github.com/user-
attachments/assets/d52eb74f-5b79-4d52-9401-1bdc2dcc304d" />

Closes #1600

vendored/sqlite3-parser/src/parser/ast/mod.rs

@@ -1655,6 +1655,8 @@ pub type PragmaValue = Expr; // TODO
 #[derive(Clone, Debug, PartialEq, Eq, EnumIter, EnumString, strum::Display)]
 #[strum(serialize_all = "snake_case")]
 pub enum PragmaName {
+    /// set the autovacuum mode
+    AutoVacuum,
     /// `cache_size` pragma
     CacheSize,
     /// `journal_mode` pragma