Storage flattening (big map, contract, rolls)

Context

This MR implements the flattening of the storage (big map, contracts, rolls)

Reopen MR : metastatedev/tezos!231 (closed)

Manually testing the MR

There is two things to test in this MR,:

• storage are correctly flattens:

  1. start a sandbox node and create new contracts, big maps, delegates,etc...
  2. inspect the storage.

• storage are correctly migrates:

  a migration on a real context then inspect the storage + difference, see

  • doc: how to test a protocol proposal and;
  • !2315 (merged)

Checklist

• add migration test with tezt, as done for 007 -> 008 in !2356 (closed)

• fix stack overflow error #1100 (closed)

  Rpc .../raw/bytes/contracts on a mainnet context fails with stack overflow. The fautive non-tail recursive function is Block_directory.read_partial_context