UI element text alignment

[maluoi]

Describe the feature

Currently, UI.Button always center-aligns text. For auto-width buttons this is reasonable, since there's no extra room for an explicit alignment to be useful. But for explicitly sized elements, the fact that text is center-aligned can become obvious, and this raises the need for explicit control.

To resolve this, any explicitly sized UI element with text should have a text alignment and text fit parameter. In this case, the parameters can be appended to the end of the existing function's list and provided with default values. The same can likely be done in C#.

In particular, these functions:

ui_label_sz
ui_label_sz_16
ui_button_sz
ui_button_sz_16
ui_button_at
ui_button_at_16
ui_button_img_sz
ui_button_img_sz_16
ui_button_img_at
ui_button_img_at_16
ui_toggle_sz
ui_toggle_sz_16
ui_toggle_at
ui_toggle_at_16
ui_toggle_img_sz
ui_toggle_img_sz_16
ui_toggle_img_at
ui_toggle_img_at_16