Range of font size and color to tagcloud

[1v9]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines.
• 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 new features).

PR Type

What kind of change does this PR introduce?

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

What is the current behavior?

Font color or size of tagcloud can't be customized.

What is the new behavior?

• Screenshots with this changes:
  

How to use?

In NexT _config.yml:

tagcloud:
  enable: true
  min: 50
  max: 100
  start: green
  end: '#5c50e6'

Does this PR introduce a breaking change?

• Yes.
• No.

[ivan-nginx]

Don't forget about docs. 👍

[ivan-nginx]

https://theme-next.org/docs/theme-settings/#Tagcloud

Need to add something like description: Available under 7.1.0 version or highter.

[1v9]

@ivan-nginx Done. I will never edit docs in the original repo. It is too dizzy 🍳.