TOB-FUEL-21: Startup warnings are not logged due to wrong import

[xgreenx]

Description

The fuel-core node imports logging macros (like info!, warn!, or error!) from the log facade instead from the tracing. Messages logged through the log facade do not get printed to the terminal and get ignored silently. Both facades are provided by the respective dependencies tracing and log.
The following code highlights a wrong import.

Figure 21.1: Import from the log facade instead of tracing. (fuel-core/bin/fuel-core/src/cli/run.rs#47–51)

use tracing::{
    info,
    log::warn,
    trace, 
};

The wrong import is used in the following figure to print a warning.

Figure 21.2: Usage of wrong import. (fuel-core/bin/fuel-core/src/cli/run.rs#260–262)

if consensus_key.is_some() && trigger == Trigger::Never {
    warn!("Consensus key configured but block production is disabled!")
}

Exploit Scenario

An attacker controls the configuration and is able to enable debugging options. Because relevant warnings during startup are not logged it is not possible to audit the node.

Recommendations

Short term, make sure that the log facade is not used.
Long term, enforce that the log facade is not used by using a clippy lint. Alternatively, configure the log facade to output messages to the terminal as well. The formatting of these messages could indicate an additional warning that the wrong facade is used.

[xgreenx]

Accidentally fixed in #1257, but still it is better to add lint rule to avoid that in the future.