Selecting where to save app

[willser]

egui use directories_next store data.This is docs about directories_next.
One way to app could selecting where to save data is following this issue emilk/egui#914 .

Other way is rewrite following code

weaver/src/main.rs

Lines 134 to 147 in 9e097f3

	fn setup(
	&mut self,
	ctx: &egui::Context,
	_frame: &epi::Frame,
	storage: Option<&dyn epi::Storage>,
	) {
	// Load previous app state (if any).
	if let Some(storage) = storage {
	// TODO change key in feature
	*self = epi::get_value(storage, epi::APP_KEY).unwrap_or_default();
	}
	// Init font after load data from local
	self.settings.local_settings(ctx);
	}

It is worth noting that those code just work in write data to hd.