add monero reward support

[Wszl]

PR Checklist

Please check if your PR fulfills the following requirements:

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

now , reward has new reward type

Issue Number(s): N/A

What is the new behavior?

add monero reward support

• Screens with this changes: N/A
• Link to demo site with this changes: Wszl's blog

How to use?

In NexT _config.yml:
add item to reward

monero:  /images/monero.jpg
...

Does this PR introduce a breaking change?

• Yes.
• No.

[ivan-nginx]

Feature will be added soon in NexT v7 pull.

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NexT is rebased into organization repo.
If you want new feature, please, create pull in NexT v6.x / v7x repo.
There is instructions on English or Chinese how to update from v5.1.x to v 6.x

You also may read this for details.