Add option to move the box relative to the screen size (#964)

## What are the changes about?

Added a new option in the configuration file for moving the box relative to the screen size.

```
box_h_position = 0.5
box_v_position = 0.5
```

The big clock is centered relative to the box. In the cases where it would be outside of the screen, it moves the box to fit in the screen.

## What existing issue does this resolve?

Add more options for personalization

## Examples

Normal usage:
```
box_h_position = 0.15
box_v_position = 0.35
```
![image](/attachments/6595dfa9-aade-45f4-887c-e5db7f8d5a89)

Clock would be outside of the screen vertically:
```
box_h_position = 0.15
box_v_position = -1.0
```
![image](/attachments/0d6bdcc4-e9dd-4671-a65d-b8b9f063ffb6)

Clock would be outside of the screen horizontally and vertically:
```
box_h_position = -1.0
box_v_position = -1.0
input_len = 3
```
![image](/attachments/630b07fd-b400-4e71-8a67-1baf3a6700a0)

Clock would be outside of the screen horizontally and vertically on the bottom left of the screen:
```
box_h_position = 2.0
box_v_position = 2.0
input_len = 3
```
![image](/attachments/28902967-11a8-4c02-a4c9-1b92f9a728ee)

## What existing issue does this resolve?

_Replace this with a reference to an existing issue, or N/A if there is none_

## Pre-requisites

- [x] I have tested & confirmed the changes work locally
- [x] I have run `zig fmt` throughout my changes

Co-authored-by: AnErrupTion <anerruption+codeberg@disroot.org>
Reviewed-on: https://codeberg.org/fairyglade/ly/pulls/964
Reviewed-by: AnErrupTion <anerruption+codeberg@disroot.org>

src/config/Config.zig

@@ -23,6 +23,8 @@ bigclock_12hr: bool = false,
 bigclock_seconds: bool = false,
 blank_box: bool = true,
 border_fg: u32 = 0x00FFFFFF,
+box_position_h: f32 = 0.5,
+box_position_v: f32 = 0.4,
 box_title: ?[]const u8 = null,
 brightness_down_cmd: [:0]const u8 = build_options.prefix_directory ++ "/bin/brightnessctl -q -n s 10%-",
 brightness_down_key: ?[]const u8 = "F5",