Charts[Gateway] Add Gateway API Route For Hedera Explorer

[leninmehedy]

Feature to Enhance

Need to be able to to expose hedera-explorer using a Gateway Port

Requested Enhancement

Expose a port for hedera-explorer through Gateway API. For now we can expose it at 8888

Business Need

This enables users to view the hedera-explorer running within the cluster.

Additional Context

No response

[leninmehedy]

Here are some existing routes for reference: https://github.com/hashgraph/full-stack-testing/tree/main/charts/fullstack-deployment/templates/gateway-api

We need to add httproute in a new yaml file: hedera-explorer-routes.yaml similar to envoy-grpc-web-routes.yaml
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