feat: Add Umami analytics and view count to article details

[tsanie]

This PR introduces umami analytics for articles and displays a pageview tag after the reading time, as shown below:

Users can enable it by putting these parameters in a configuration file such as hugo.yaml:

params:
  analytics:
    umami:
      enabled: true
      host: https://u.example.com # your umami service URL
      siteId: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
      token: # not required, you can use the cloudflare worker proxy, see https://blahba.com/en/p/using-umami-with-cloudflare-worker/
      startAt: # Date constructor parameters, such as `1735689600000` or `2025-01-01`

You can get a token via POST /api/auth/login with data { "username": "<your user>", "password": "<password>" }.

If you are worried about leaking the token, you can wrap it with a Cloudflare Worker, see this article: https://blahba.com/en/p/using-umami-with-cloudflare-worker/

[CaiJimmy]

Hi! Thanks for the pull request, and sorry for the late reply.

I think this feature is too specific and it wouldn't make sense to make it available in the theme.

Thanks again!