App dashboard stats latest hour

[relft]

hi,

It will be great to add stats latest 1, only required add apps/OpenEnergyMonitor/graph-nav.php

add
<button class='visnav time btn btn-inverse btn-link btn-large py-1 px-2' time='1'>1<?php echo _('h') ?></button>

after change file is

1 3 6 + - < >

Please anybody can add an add to master branch, tested in my local environment and it works without any issue

Thanks