Prepare Pontus-X explorer for their MVP

[csillag]

The Pontus-X project is going to have their MVP release soon, and for that, they need some new features for the Explorer.

Wanted frontend features:

• Make it possible to show Pontus-X DevNet, Pontus-X TestNet, and Oasis Sapphire layers
• Differentiate between the 3 layers using themes and appropriate labels everywhere
• Tune the layer selector to be nice (fold networks into one)
• Support account name resolution based on the Pontus-X identity dictionary even on
• [UX]: Display token name in TXs to/from smart contracts #1692 (not required, just preferred)

Relevant backend tasks:

• Missing token data on the pontusxtest paratime nexus#881

Our process:

• Discuss the requirements with deldaDAO
• Implement the require new features on the pontus-x branch of Explroer
• Iterate with deltaDAO until they are satisfied
• Break out as much as possible from the new features into separate PRs so that we can merge them back to the master branch, to minimize the delta
• Go through the code review process, iterate until everyone is satisfied, and the merge them
• Rebase the pontus-x branch on top of the finalized base features

Pending PRs:

• Fix case sensitivity in Pontus-X account name resolution #1685
• Support for more granular configuration for hiding layers #1686
• Tune displaying account names #1687
• Add support for merging all networks in the layer selector  #1688