Support gRPC to query MaxMind database in GeoIP plugin

[runderwo]

Is your feature request related to a problem? Please describe.
The GeoIP plugin can only operate on a flat file and does not query a service.

Describe the solution you'd like
We would like to query a local cache of the MaxMind database that we expose via a gRPC interface. We would like the plugin to offer a way to fetch database entries from HTTP and gRPC endpoints so that we can point it to our internal caching service.

Describe alternatives you've considered

Additional context

[agup006]

@cosmo0920 is this something we can achieve using WASM?

[cosmo0920]

Unfortunately, no. This is because WASM or WASI on wasm-micro-runtime does not implement socket interface completely. So, we're not able to implement network stack required programming model in filter_wasm mechanism, I'm afraid.