allow config of initial and throttled lograte and time unit

[the-clam]

modified OtlpConfigUtil.java to take in:

otel.exporter.otlp.lograte
otel.exporter.otlp.throttledlograte
otel.exporter.otlp.logtimeunit

and configure the necessary values to set the log rate and throttled log rate for ThrottlingLogger.Java

[the-clam]

#7178

[jkwatson]

@the-clam We'll need to connect with @jack-berg when he's back from leave about how this should be configured. I suspect that there will be some debate about this, since these new configuration options will be java SDK specific, and there may be a desire to have a general non-java-specific configuration option that is specified officially.

This is just to say that it might take a bit to get this landed, due to us wanting to make sure we have a long-term support plan for how this is configured.

[the-clam]

@jkwatson Sounds good, I'll keep an eye out for any updates.