[next] refactor: drop md5 dependency for usernameToColor and migrate to TS

[susnux]

☑️ Resolves

• Migrate to Typescript
• Simplify
• Remove useless dependency on md5

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 3️⃣ Backport to next requested with a Vue 3 upgrade

[max-nextcloud]

I think the color returned by this function used to match the one computed by the server as a background color for the avatar: https://github.com/nextcloud/server/blob/776a689e09aea18dd455b885bdb575849b525d3e/lib/private/Avatar/Avatar.php#L256

I think it would be nice to maintain that property - so you can compute the color of he default avatar on the client side. I'd like to use this in text for the author indicator so it matches the user avatar if the user did not change it.

So what's the best way forward here? Reimplementing the simple hash in php in the server function?

update: just noticed we don't need it in text as colors are computed on the server anyway.

[susnux]

Yes basically this is "never" used as there is always the initials avatar returned by server. Its only about is-no-user of the avatar component