rpcdaemon: add support for rotating log files of external interfaces

[canepat]

This PR introduces a new abstraction to produce rotating log files tailored for external interfaces (e.g. JSON-RPC API), which means logging incoming requests and outgoing responses, possibly filtered according to some application-level need (e.g. slow latency request/response, whatever slow means depending on the context). The proposed implementation relies on usage of spdlog, choosing the best performance-wise library is left as a further optimisation, if proven necessary.

The foreseen usages are:

• adding a command-line option to enable interface logging for Engine API endpoint: when enabled, it seems reasonable to log all requests/responses for debugging purposes
• adding some command-line options to enable interface logging for Execution API endpoint: when enabled, it can be useful to log only request/response with latency greater than some specified threshold (e.g. only request/response taking more than 30sec to be served) or some specific API for debugging purposes (e.g. only eth_call)

This PR doesn't introduce any activation or usage of the feature yet.

Moreover, the following minor changes are added:

• infra: default settings in logging initialisation function
• conan: fix some linter warnings