Allow direct embedding of embed.FS files

[wneessen]

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

In this discussion: #27 (reply in thread) I was made aware, that users might want to embed/attach files via embed.FS - meaning files that are directly shipped in the go binary. This is currently possible via opening the embed.FS file and then using EmbedReader. We might consider adding direct embed.FS support for ease of use.

Describe the solution you'd like

I see two possible solutions:

• Add two new EmbedEmbedFSFile() and AttachEmbedFSFile() methods
• Add a new FileOption that hands over the embed.FS to either EmbedFile() and AttachFile() methods that then decide from where to fetch the file.

Describe alternatives you've considered

No response

Additional context

No response