Update README.md w/ new node solution

[sz3k]

Minor non-app-functional adjustment to add a link to Citadel (https://runcitadel.space/) to Full Node Solutions

Description

Relates to issue: ZEUS-0000

Please enter a description and screenshots, if appropriate, of the work covered in this PR

This pull request is categorized as a:

• New feature
• Bug fix
• Code refactor
• Configuration change
• Locales update
• Quality assurance
• [ X] Other

Checklist

• [] I’ve run npm run tsc and made sure my code compiles correctly
• I’ve run npm run lint and made sure my code didn’t contain any problematic patterns
• I’ve run npm run prettier and made sure my code is formatted correctly
• I’ve run npm run test and made sure all of the tests pass

Testing

If you modified or added a utility file, did you add new unit tests?

• No, I’m a fool
• Yes
• [X ] N/A

I have tested this PR on the following platforms (please specify OS version and phone model/VM):

• Android
• iOS

I have tested this PR with the following types of nodes (please specify node version and API version where appropriate):

• LND
• c-lightning-REST
• spark
• Eclair
• LndHub

Locales

• I’ve added new locale text that requires translations
• I’m aware that new translations should be made on the Zeus Transfix page and not directly to this repo

Third Party Dependencies and Packages

• Contributors will need to run npm install after this PR is merged in
• 3rd party dependencies have been modified:
  • verify that package.json and package-lock.json have been properly updated
  • verify that dependencies are installed for both iOS and Android platforms

Other:

• [X ] Changes were made that require an update to the README
• Changes were made that require an update to onboarding