Add hexo-tag-chart

[shen-yu]

Awesome Contribution Checklist:

• [x] I have read, and re-read the Contributing Guidelines
• [x] I have searched to ensure the suggested item doesn't exist on this list
• [x] This PR contains only one item

Please Describe Your Addition

Insert Chartjs in Hexo by using tags. Demo

[shen-yu]

Can a reviewer take a look at this please ?

[benmccann]

I sort of wonder about this one. It will be useful to an extremely small portion of Chart.js users. Other integrations we list are primarily for languages where we can cover most languages with a fairly small number of integrations. But there's tons of different blogging platforms and most people won't be building blogs to begin with. I think that if you were trying to discover how to insert a chart into hexo you'd be much more likely to search hexo resources than chart.js resources. My concern here is making the list cluttered with items that won't be useful to many users