Add support for unlimited map size

[saxena-anurag]

There are some production cases possible where it is hard to predict the maximum map size that will be needed beforehand. HVCI requirements (hence native modules) also makes harder to change the map size at runtime.

One possible solution for this is to support unlimited map size. This support can be added for all maps except array map types, and LRU hash. This should not cause any verification or safety issues, at the same time allowing unlimited size for hash maps.

Proposal

1. User passes 0 map size to indicate unlimited entries.
2. If map size is unlimited, ebpfcore chooses a larger bucket count than the current default.
3. Any possible verifier changes to allow 0 map size n the verification step.

[saxena-anurag]

Proposal: Instead keep using non-0 map size, but ebpfcore ignores the max size. Most likely the same is done by Linux.