Queries cause crash after a few days

[jcalbert]

Not well documented yet, but after a long time / large number of queries, Legacy Eagle device stops responding, gives blinking status light

[toddsay]

I'm not certain if this is the same issue I've been discussing here https://community.home-assistant.io/t/custom-component-rainforest-eagle-200-local-meter-reader/110656/94, but if so, I have a pull request which may help #8. Basically, in my experience the legacy Eagle stops responding after a few hours or days, returning a 503 error with text "Timeout waiting for response".

Through trial-and-error I discovered that it is possible to get things running again by sending the get_historical_data request to the cgi_manager endpoint (as used by the web interface). After sending this request and waiting several seconds, the requests used by this client will typically begin working again. This PR automates that workaround process.