Revert all changes related to storing and restoring non-rel data in page server

This includes the following commits:

35a1c3d521 Specify right LSN in test_createdb.py
d95e1da742 Fix issue with propagation of CREATE DATABASE to the branch
8465738aa5 [refer #167] Fix handling of pg_filenode.map files in page server
86056abd0e Fix merge conflict: set initial WAL position to second segment because of pg_resetwal
2bf2dd1d88 Add nonrelfile_utils.rs file
20b6279beb Fix restoring non-relational data during compute node startup
06f96f9600 Do not transfer WAL to computation nodes: use pg_resetwal for node startup

As well as some older changes related to storing CLOG and MultiXact data as
"pseudorelation" in the page server.

With this revert, we go back to the situtation that when you create a
new compute node, we ship *all* the WAL from the beginning of time to
the compute node. Obviously we need a better solution, like the code
that this reverts. But per discussion with Konstantin and Stas, this
stuff was still half-baked, and it's better for it to live in a branch
for now, until it's more complete and has gone through some review.

postgres_ffi/build.rs

@@ -18,8 +18,6 @@ fn main() {
         // included header files changed.
         .parse_callbacks(Box::new(bindgen::CargoCallbacks))
         .whitelist_type("ControlFileData")
-        .whitelist_type("CheckPoint")
-        .whitelist_type("FullTransactionId")
         .whitelist_var("PG_CONTROL_FILE_SIZE")
         .whitelist_var("PG_CONTROLFILEDATA_OFFSETOF_CRC")
         .whitelist_type("DBState")