polygon-edge.sh now checks if jq is installed

[criadoperez]

Description

Scripted polygon-edge.sh assumed jq is installed.
It now checks if it is. If it is, its proceeds. If it isn't it exits the script and informs the user.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)