Everything involving "logLevel" is awful

[exo-pla-net]

Given

new ErrorReporting(initConfiguration?: ConfigurationOptions)

and

export interface ConfigurationOptions {
    logLevel?: string | number;
   ...
}

A user has no idea what "logLevel" means / will induce with the error report. Allowing it to be a string or a number has a rather wide possibility space! And what it does is not mentioned in the docs.

I think what was intended was for "logLevel" to represent Severity.

I furthermore think that, instead of the type being:

logLevel?: string | number

It was intended to be / ought to be:

logLevel?: LogLevel

Per google-cloud\error-reporting\build\src\configuration.d.ts:

export type LogLevel = 'error' | 'trace' | 'debug' | 'info' | 'warn' | 'fatal' | undefined;

I propose that "logLevel" be renamed "severity", with:

export interface ConfigurationOptions {
    severity?: LogSeverity ;
   ...
}

and

export type LogSeverity = 'error' | 'trace' | 'debug' | 'info' | 'warn' | 'fatal' | undefined;

I furthermore propose that LogSeverity be mentioned in the docs.