feat(bar): floating center area for widgets

* Added a new floating area at the center of the bar
* Optional center widgets config, fixed spacing on the center widget
* Turning transparency on by default

komorebi-bar/src/render.rs

@@ -190,6 +190,7 @@ impl RenderConfig {
             left: match self.alignment {
                 Some(align) => match align {
                     Alignment::Left => spacing,
+                    Alignment::Center => spacing,
                     Alignment::Right => 0.0,
                 },
                 None => 0.0,
@@ -197,6 +198,7 @@ impl RenderConfig {
             right: match self.alignment {
                 Some(align) => match align {
                     Alignment::Left => 0.0,
+                    Alignment::Center => 0.0,
                     Alignment::Right => spacing,
                 },
                 None => 0.0,