Additional metadata options, text rotation, support for Opentype fonts

[bladerail]

Hi, I've been experimenting in a local fork and added support for additional metadata options in the yaml files, namely horizontal and vertical alignment, outlineWidth, outlineColor. These already had the core features present, so it was relatively simple to add in the yaml options.

I wanted to rotate text for the change-my-mind meme template, so I experimented with using the fogleman/gg library instead of the current image library. I managed to do it and thus the metadata can now accept text slots with a rotation value in degrees.

Lastly, I modified the font support to accept OTF fonts as well.

I'm mentioning all these as I understand that there is a Contribution checklist. These are features that do not yet have a ticket and they are definitely changes of more than 20 lines of code, so I was hoping that this could become the ticket.

[catalintomai]

Hi @bladerail , are you open to submit a PR for the changes you are proposing? Thanks.