### Is your feature request related to a problem? Please describe.

- old painting app JINZO Paint (PocketPC, Windows CE) saves images as 2-bit

`magick` complains:
```
% magick shartoise.2bp -colors 4 -type palette shartoise.bmp
magick: unsupported bits per pixel `shartoise.2bp' @ error/bmp.c/ReadBMPImage/987.
```

### Describe the solution you'd like

- support for reading and writing such files

### Describe alternatives you've considered

GOOD
- GraphicConverter 11 opens them
- macOS (Preview, QuickLook, Acorn, etc) opens them

BAD
- Photoshop 2023 does not open them


### Additional context

Example files: [Archive.zip](https://github.com/ImageMagick/ImageMagick/files/14003214/Archive.zip)
- shartoise.bmp
- shartoise.2bp

`file` reports:
```
shartoise.2bp: PC bitmap, Windows 3.x format, 480 x 296 x 2, image size 35520, cbSize 35590, bits offset 70
shartoise.bmp: PC bitmap, Windows 3.x format, 480 x 296 x 4, image size 71040, cbSize 71158, bits offset 118
```

reference image (PNG)
![shartoise](https://github.com/ImageMagick/ImageMagick/assets/49612/631671ca-87fc-46d6-9041-e1148a31ca2a)

Support for 2-bit bitmap
This is a GitHub Issue
repo:ImageMagick
owner:ImageMagick
Title : Support for 2-bit bitmap
Issue date:

--- start body ---
### Is your feature request related to a problem? Please describe.

- old painting app JINZO Paint (PocketPC, Windows CE) saves images as 2-bit

`magick` complains:
```
% magick shartoise.2bp -colors 4 -type palette shartoise.bmp
magick: unsupported bits per pixel `shartoise.2bp' @ error/bmp.c/ReadBMPImage/987.
```

### Describe the solution you'd like

- support for reading and writing such files

### Describe alternatives you've considered

GOOD
- GraphicConverter 11 opens them
- macOS (Preview, QuickLook, Acorn, etc) opens them

BAD
- Photoshop 2023 does not open them


### Additional context

Example files: [Archive.zip](https://github.com/ImageMagick/ImageMagick/files/14003214/Archive.zip)
- shartoise.bmp
- shartoise.2bp

`file` reports:
```
shartoise.2bp: PC bitmap, Windows 3.x format, 480 x 296 x 2, image size 35520, cbSize 35590, bits offset 70
shartoise.bmp: PC bitmap, Windows 3.x format, 480 x 296 x 4, image size 71040, cbSize 71158, bits offset 118
```

reference image (PNG)
![shartoise](https://github.com/ImageMagick/ImageMagick/assets/49612/631671ca-87fc-46d6-9041-e1148a31ca2a)

--- end body ---
