feat: use ocis images from same directory level

[saw-jan]

Description

FEAT: able to use images available at the same directory level as the markdown file in the ocis server.

Requirements:

1. allow to embed images that are stored in the same folder or its subfolders by using the markdown image syntax

same folder - :heavy_check_mark: subfolders - :x: (Follow up in next PR)

2. not allowing to embed files from a folder of higher levels

:heavy_check_mark:

3. require the whole folder be publicly shared if the public viewer should see the images

:heavy_check_mark:

4. if only the markdown file is publicly share the viewer should not be able to access the images

:heavy_check_mark:

Test Cases:

• local images (image from current directory level)
• large local images
• multiple small images (if images are large then only one might be visible)
• uploaded image (upload into markdown)
• external image url
• audio/video (doesn't work - not supported by the md parser)

Related Issue

• Part of #27

Screenshots (if appropriate):

Owner:

Folder Link - Viewer:

MD File link - Editor:

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Tests only (no source changes)
• [ ] Documentation only (no source changes)
• [ ] Maintenance (e.g. dependency updates or tooling)

Checklist:

• [x] Code changes
• [ ] Unit tests added
• [ ] Acceptance tests added
• [ ] Documentation updated

[saw-jan]

This PR will be merged to the main branch which will be v2.0.0. We have released v1.0.0

@grgprarup @S-Panta I have updated the comments. Please re-check if it works