Add Tag Manager for Better Analytics about the Usage of Harbor

[Vad1mo]

This PR adds Google Tag Manger. Given that, in the next step we can add google Anaylticy and other tools.

With that information, we can better deducts, what features are heavily used in harbor and what version of harbor the majority of users are running.

[Vad1mo]

As Mentioned, I would like to outline some advantages I think we can gain from analyzing traffic

1. Identifying Most Used Documentation and their Versions: We can track page views to see which versions of our documentation are most accessed by users. This understanding can guide us on where to focus our update efforts.

2. Determining Our Popular Documentation Material: Google to analyze the behavior flow and the time users spend on different pages. This way, we can identify which documentation materials are most popular and create more or better content and, on the other hand, remove content not needed.

3. Understanding User Engagement with Our Documentation: can help us understand which documentation users are returning to read more than once. These could be documents that are either very useful or possibly confusing and needing improvement.

4. Assessing Interest in Joining Our Community: We can set up goals in Google Analytics to track specific actions, such as clicking on a ‘Join the Community’ button. This can give us a clear idea of how many users are interested in becoming more involved with our project.

Every maintainer will have access to the analytics platform.

[OrlinVasilev]

@Vad1mo can we see the statistics from the preview deployment? Details do you have a link or something otherwise +1