Add support for PieFed tags/flairs

[hjiangsu]

Pull Request Description

This PR adds support for viewing PieFed flairs/tags in posts. Flairs will only show up on the feed when viewing it from the community feed to reduce potential clutter (this also matches the implementation on PieFed's web app). Both tags and flairs will be shown when viewing the post itself and through the post bottom sheet.

Additionally, you'll be able to attach flairs/tags when creating posts. This was tested briefly and it all seems to work as expected. Note that there will likely be a follow up PR to clean up the logic within the CreatePostPage as it's handling a lot of logic related to metadata fetching.

Issue Being Fixed

Issue Number: N/A

Screenshots / Recordings

Checklist

• If a new package was added, did you ensure it uses an appropriate license and is actively maintained?
• Did you use localized strings (and added appropriate descriptions) where applicable?
• Did you add semanticLabels where applicable for accessibility?