feat: add partner params that return the sum of them

[DarkGhost7]

For the endpoint /partners/<partner>/<param> of a new endpoint such as /partners/<partner>/<param>/sum or ?summed=true
either make a new query or add at the end of this query a summed account of what they are asking

SUM_QUERY_PAR_INDIV = """sum((partners{{partner=\"{0}\", param=\"{1}\"}}))"""
This is the summed expression.