Add matomo as an analytics provider

[foliet]

PR Checklist

• The commit message follows guidelines for NexT.
• Tests for the changes was maked (for bug fixes / features).
  • Muse | Mist have been tested.
  • Pisces | Gemini have been tested.
• Docs in NexT website have been added / updated (for features).

PR Type

• Bugfix.
• Feature.
• Code style update (formatting, local variables).
• Refactoring (no functional changes, no api changes).
• Documentation.
• Translation.
• Other... Please describe:

What is the current behavior?

There's no support for Matomo Analytics
Issue resolved: None

What is the new behavior?

Simple change. It does work if you can see three http requests about matomo as shown below.

• Link to demo site with this changes: None
• Screenshots with this changes:
  

How to use?

In NexT _config.yml, line 696:

# Matomo Analytics
# See: https://matomo.org/
matomo:
  enable: false
  server_url: # https://www.example.com/
  site_id: # <your site id>

Notes

I haven't updated the docs and I will finish it after this PR being accepted. This is my first PR in my life, so please correct me if there is any mistake.

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All committers have signed the CLA.

[coveralls]

Pull Request Test Coverage Report for Build 2784829291

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.468%

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Totals
Change from base Build 2772219653:	0.0%
Covered Lines:	138
Relevant Lines:	141

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💛 - Coveralls

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