Serve the explorer from a subfolder in a staging environment

[ascartabelli]

Summary

Before serving the explorer from a local node, we need to field test that everything works as intended.

Right now the staging env. for the explorer is https://explorer-staging.dusk.network/

To make this test we should serve it from something like https://staging.dusk.network/explorer/ and set the proper env variable: VITE_BASE_PATH="/explorer"