docs: improve configuring-a-plugin page clarity and add community plugins link#6731

tanupriyasingh1 wants to merge 1 commit intopipe-cd:masterpipe-cd/pipecd:masterfrom

tanupriyasingh1:fix/configuring-plugin-docstanupriyasingh1/pipecd:fix/configuring-plugin-docsCopy head branch name to clipboard