feat: add ability to hide posts in blog overview

[otherpaco]

I wanted to use the starting page as blog.
But then all entries like "/about" or "/imprint" will show up as posts as they all are in the same folder content.

I added a param hideOnBlog to the front matter. That parameter will prevent the file from being listed in the blog overview but it is still accessible.

Here is a linkt to the code of a wip blog that shows what I want to achieve:

https://codeberg.org/otherpaco/p11io-hextra

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[imfing]

Thank you, I like this idea. I will take a look

[otherpaco]

Dear Xin, it realized there is much more to do and check to use the starting page as blog.
I will keep on modifying my blog an will come back with a better PR or a feature request.

I removed the new parameter because I can simply use

{{- if eq .Params.type "blog" -}}

instead of

{{- if not .Params.hideOnBlog -}}

But there are more places I would need to add that e.g. layouts/partials/components/pager.html

Maybe it would be easier going with collections.Where gohugo docs

Feel free to close this PR and I could move the info to an issue if you prefer it that way.

Have a nice weekend