Add support for custom meta tags

Note to myself: Would once again be helpful as full replacement for https://www.drupal.org/project/tracking_code → to add validation snippets (which are not supported by Metatags module) to the head!

Would something like Custom Meta → satisfy that request? Seems to fit the request to me.

@pookmish indeed that looks good for such cases!

Would you still be fine with integrating similar functionality into asset_injector (if the community / we implement it) or do you think it's totally different from that asset_injector is supposed to do?

I think it's still quite similar and could be helpful to have these three features in one module instead of having to use separate modules... but I'll also think about it again. Just would like to have your opinion here and know if there's a chance to integrate it anyway.

@pookmisch would you be fine to add this function to have all these three options combined in this module? I'd really love that instead of having to use one further module for something very similar. Furthermore asset_injector already has settings / options to select conditions where this should be added.

Of course, we'd prepare the code.

The plan would be to add a third inject type for meta. Similar to how custom_meta → solves it (see screenshot → ) you could then select the attribute and its content. Eventually we should allow multiple instead of just one?

So I think there would even be some more features out of the box in comparison to custom_meta, but having one module for these three related things is also a good thing from my perspective.

Technical reference:
https://drupal.stackexchange.com/questions/217880/how-do-i-add-a-meta-ta...

@pookmish would you accept if we added this? I wouldn't like to invest time (& money) here for something that won't get merged. Still, I would like to invest time (& money) for a feature that I think would be great to have included (see previous comments).

@pookmish re #3 I just ran into another case of a "metatag" that should be added in UI and the custom_meta module isn't able to handle, while it would be great to use asset_injector as swiss-army knife:

Adding <link rel="alternate" type="application/rss+xml" href="https://example.com/technology/feed/" /> doesn't seem possible (background: RSS link https://developers.google.com/search/docs/appearance/google-discover?hl=de)

So if you could green-light for merging such a feature, may it be included directly or as submodule, that would be fabulous!