Client code base clean up for subspaces

[techsmyth]

Description

As a I want So that

Acceptance criteria

To be cleaned up:

• [ ] Cards: Space vs SpaceSubspace (new) vs SubspaceCard (old ChallengeCard)
• [ ] Opportunity route, all Opportunity pages and Opportunity layout (+admin)
• [ ] rm Opportunity Context, useOpportunity
• [ ] All Challenge pages except Home
• [ ] Try to remove JourneyTypeName or at least minimize usage
• [ ] From JourneyLevel, JourneyPath and SpaceType pick what suits most usages

Additional Context

Figure out whether SpaceType is to stay. If it's related to Space Template, then decide what's rendered based on SpaceType and what on JourneyLevel or Path (icon may be on SpaceType while the word subspace vs space may depend on the level/path).

Cards:

• src/domain/journey/subspace/subspaceCard/SubspaceCard.tsx extends src/domain/journey/common/SpaceChildJourneyCard/SpaceChildJourneyCard.tsx (merge? child journey = subspace now)
• src/domain/journey/space/SpaceSubspaceCard/SpaceSubspaceCard.tsx used on /spaces page
• src/domain/journey/space/SpaceCard/SpaceCard.tsx used on MyDashboard and similar

Areas that will be affected

To be added during the refinement