Add Prominent Link to Yomichan Migration

[MarvNC]

As there is still an extremely large base of Yomichan users, I think we could have a button or something linking to the migration page on the homepage.

https://yomitan.wiki/other/yomichan-migration/

[jamesmaa]

As there is still an extremely large base of Yomichan users

What is your basis of this observation? It runs against my own assumptions

[MarvNC]

No doubt it's in decline, but you'd be surprised how many people just don't bother. I think it'd be worth addressing still with the incoming forced deprecation of mv2.

[MarvNC]

Resolved by #58