Prototype: 64-Bit Main Memory for Motoko

[luc-blaeser]

DO NOT MERGE

Prototype for related to ideas of enhancing Motoko's orthogonal persistence:

• Extend the main memory to 64-bit (still transient in this PR).
• Limit the number of page accesses on main memory per message.
• Provide a 64-bit IC API.
• Automatic detection of 32-bit or 64-bit Wasm execution.

Related PRs for more details:

• IC Enhanced Orthogonal Persistence Support for Motoko: https://github.com/dfinity/ic/pull/143
• Motoko 64-Bit: https://github.com/dfinity/motoko/pull/4136
• Motoko Stable Heap for Scalable Upgrades: https://github.com/dfinity/motoko/pull/4225