Make PortalJS Discord the official community channel (separate from DataHub.io)

[anuveyatsu]

Use the existing PortalJS Discord as the official community space for PortalJS; keep DataHub.io Discord for broader data community topics.

Motivation

• Clearer contributor onboarding and support.
• Stronger brand alignment for PortalJS.
• Reduces confusion about where to ask PortalJS-specific questions.

Discord (make sure our invite link won't expire): https://discord.gg/6FVDkU6Jg

Note that you need to be added to the Team on Discord so that you can manage the discord server.

Tasks

• Update README and docs with the PortalJS Discord invite link.
• Update portaljs.com site header/footer/community link.
• Check if we have links somewhere eg on GitHub repo
• Post pinned announcements in both servers.
• Create Github channel and integrate portaljs repo so that we can have posts about activities in the repo such as new issues, new comments in the issues, PRs etc. Check out Flowershow server for reference.

[anuveyatsu]

@willy1989cv could you update this issue pls?