feat(hashtag-column): allow multiple hashtags

[fernandolguevara]

[jb55]

we can accept this for now but I was hoping we could have an actual ui for this

[jb55]

This is not really enough. we need to build on this and represent the TimelineKind as Vec<String> for hashtag instead of just String, otherwise it will not be serialized properly, unless we want to have this hacky representation that we always have to parse everywhere... which I'm not sure I'm happy about

[fernandolguevara]

@jb55 can you review this PR again, please?

[jb55]

checking now, sorry for the delay

[jb55]

thx boss!