Scenariomip update

[laurinks]

Purpose of this PR

Changes made in two steps:

1. Updating existing mapping with new variable list
2. Update Tiers according to Daniel's list (these are the correct ones, as double checked with him)
3. Checking existing mappings for additional piam_variables

In two steps, piam_variables in the following categories were added (see git diff bfebf3813932721e8af1e81542a3a597c3a66f20 ffb0aa435c1a458e2851e6e5f77152fb585dc0cd ):

• Air Pollution|PM2.5|Urban Population
• Carbon Capture|***
• Emissions|CO2|Energy|Demand|Transportation|Bus, Emissions|CO2|Energy|Demand|Transportation|Truck, Emissions|CO2|Energy|Demand|Transportation|Domestic Aviation
• Final Energy|Non-Energy Use|Chemicals
• Health|Disability-Adjusted Life Years|PM2.5
• Price|Final Energy|***
• Sales|Transportation|Bus, Sales|Transportation|Truck

Checklist:

• I did not use Excel to open csv files or checked that no side-effects occur (changed values, many new quotation marks, …)
• I added any renamed piam_variable to renamed_piam_variables.csv to guarantee backwards compatibility.

It is recommended to have a look at the tutorial before submission.