feat(dashmate): insight, core block explorer

[shumkov]

Issue being fixed or feature implemented

The platform explorer requires insight to obtain utxos for simple wallet. To enable platfrom explorer for dashmate local network we need insight to be started

What was done?

• Added insight API and UI to dashmate
• Enable insight api with yarn setup

Usage

core.insight.enabled to enable API, and core.insight.ui.enabled to UI (API must be enabled too)

Use API:

curl http://127.0.0.1:3001/insight-api/block-index/0

Open UI:

open http://127.0.0.1:3001/insight/

How Has This Been Tested?

Breaking Changes

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have added "!" to the title and described breaking changes in the corresponding section if my code contains any
• I have made corresponding changes to the documentation if needed

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone