[tox] Update doc testenv to account for documentation restructuring
* Build doc from `doc` directory.
* Use `sphinx-build` directly instead of `make` as this now works and allows
to build within .tox temporary environment (instead of doc/_build),
preferable for a "test" action.
Related to #5447161.
// This contains template-specific javascript
function filterLog(domid, thresholdLevel) {
var logLevels = ["Debug", "Info", "Warning", "Error", "Fatal"]
var action = "hide";
for (var idx = 0; idx < logLevels.length; idx++){
var level = logLevels[idx];
if (level === thresholdLevel){
action = "show";
}
$('#'+domid+' .log' + level)[action]();
}
}