Change PlutusTX to the new name Plinth and ensure this change is made across all assets under IOHK/Intersect's control

### Describe the feature you'd like

PlutusTX has been renamed to Plinth. We need to identify all assets that need to be updated, deprecated or taken offline to reflect the new name. This will need to include at least the following:
-update the logo
-github repos (Plutus repo, others?)
-Plutus online documentation (https://plutus.cardano.intersectmbo.org/docs/)
-Cardano Developer Docs - minting policy section in particular
-Education team's Plutus Pioneer program
-other assets
-Google 'Plutus Documentation' to identify and label assets that need to be updated

Marcomms ticket for this issue: https://input-output.atlassian.net/servicedesk/customer/portal/8/MR-1322?created=true

This may need to break into sub-tickets for specific tasks or work on specific sites.
- [ ] Plutus Docs Site
- [ ] Cardano Developer Docs
- [ ] Plutus Pioneer Program

### Describe alternatives you've considered

_No response_