fix: add blockscout frontend.env to deployments (circlefin#19)

## Summary
- Add frontend environment configuration for Blockscout block explorer
deployment

## Test plan

This fix `make testnet` command in readme
https://github.com/circlefin/arc-node/blob/main/README.md#local-testnet

Author: ZhiyuCircle

deployments/monitoring/config-blockscout/frontend/frontend.env

@@ -0,0 +1,26 @@
+NEXT_PUBLIC_API_HOST=localhost
+NEXT_PUBLIC_API_PROTOCOL=http
+NEXT_PUBLIC_NETWORK_NAME=Arc Localnet
+NEXT_PUBLIC_NETWORK_SHORT_NAME=Arc
+NEXT_PUBLIC_NETWORK_ID=1337
+NEXT_PUBLIC_NETWORK_CURRENCY_NAME=USDC
+NEXT_PUBLIC_NETWORK_CURRENCY_SYMBOL=USDC
+NEXT_PUBLIC_NETWORK_CURRENCY_DECIMALS=18
+NEXT_PUBLIC_API_BASE_PATH=/
+NEXT_PUBLIC_APP_HOST=localhost
+NEXT_PUBLIC_APP_PROTOCOL=http
+NEXT_PUBLIC_HOMEPAGE_CHARTS=[]
+NEXT_PUBLIC_IS_TESTNET=true
+NEXT_PUBLIC_API_WEBSOCKET_PROTOCOL=ws
+NEXT_PUBLIC_API_SPEC_URL=https://raw.githubusercontent.com/blockscout/blockscout-api-v2-swagger/main/swagger.yaml
+NEXT_PUBLIC_COLOR_THEME_DEFAULT=light
+NEXT_PUBLIC_HOMEPAGE_HERO_BANNER_CONFIG='{ "background": ["linear-gradient(81deg, #F1EBFF 0%, #E1F2FF 108.8%)","linear-gradient(72deg, #175284 0%, #342552 112.58%)"], "text_color": ["#29233B", "#ffffff"], "button": { "_default": { "background": ["#0073C3", "#1AA3FF"], "text_color": ["#ffffff", "#000000"] }, "_hover": { "background": ["#1AA3FF", "#1894E8"] } } }'
+NEXT_PUBLIC_NETWORK_ICON=https://assets.circle.com/product-apps/assets/images/Circle-Icon.svg
+NEXT_PUBLIC_NETWORK_ICON_DARK=https://assets.circle.com/product-apps/assets/images/Circle-Icon.svg
+NEXT_PUBLIC_NETWORK_LOGO=https://assets.circle.com/product-apps/assets/images/Circle-Logo-Light.svg
+NEXT_PUBLIC_NETWORK_LOGO_DARK=https://assets.circle.com/product-apps/assets/images/Circle-Logo-Dark.svg
+FAVICON_MASTER_URL=https://assets.circle.com/product-apps/assets/images/Circle-Favicon-Lg.png
+NEXT_PUBLIC_AD_BANNER_PROVIDER=none
+NEXT_PUBLIC_AD_TEXT_PROVIDER=none
+# Disable TLS verification for ZScaler
+NODE_TLS_REJECT_UNAUTHORIZED=0