Fix economy/macro --transform

[JerBouma]

As described in #3916, the transform functionality simply didn't work while being pretty important. If you would plot the GDP of a variety of countries it doesn't say much as the GDP of the United States is of course much higher than that of the Netherlands resulting in a meaningless graph. This should fix it.

(🦋) /economy/ $ macro --parameters GDP --countries Germany,France,Netherlands -s 2010-01-01 --raw --transform TPOP

          Macro Data  [Total percentage change on period]           
┏━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┓
┃                     ┃ france_GDP ┃ germany_GDP ┃ netherlands_GDP ┃
┡━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━┩
│ 2020-07-01 00:00:00 │ 14.00      │ 7.38        │ 7.11            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2020-10-01 00:00:00 │ 0.24       │ 1.49        │ 1.09            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2021-01-01 00:00:00 │ 0.97       │ -0.02       │ 0.32            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2021-04-01 00:00:00 │ 1.51       │ 1.91        │ 4.15            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2021-07-01 00:00:00 │ 3.32       │ 2.94        │ 2.66            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2021-10-01 00:00:00 │ 0.97       │ 1.34        │ 1.34            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2022-01-01 00:00:00 │ 0.75       │ 2.13        │ 2.71            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2022-04-01 00:00:00 │ 1.22       │ 1.27        │ 2.67            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2022-07-01 00:00:00 │ 1.44       │ 1.41        │ 2.18            │
├─────────────────────┼────────────┼─────────────┼─────────────────┤
│ 2022-10-01 00:00:00 │ 1.69       │ 2.13        │ -               │
└─────────────────────┴────────────┴─────────────┴─────────────────┘

Also see rename for variables:

╭─────────────────────────────────────────────────────────────────────────────────── Economy ───────────────────────────────────────────────────────────────────────────────────╮
│                                                                                                                                                                               │
│     overview           show a market overview of either indices, bonds or currencies   [WallStreetJournal]                                                                    │
│     futures            display a futures and commodities overview                      [WallStreetJournal, Finviz]                                                            │
│     map                S&P500 index stocks map                                         [Finviz]                                                                               │
│     bigmac             The Economist Big Mac index                                     [Nasdaq]                                                                               │
│     ycrv               show sovereign yield curves                                     [FRED]                                                                                 │
│     events             show economic calendar                                          [Nasdaq]                                                                               │
│     edebt              show external debt statistics for various countries             [Wikipedia]                                                                            │
│                                                                                                                                                                               │
│     rtps               real-time performance sectors                                   [AlphaVantage]                                                                         │
│     valuation          valuation of sectors, industry, country                         [Finviz]                                                                               │
│     performance        performance of sectors, industry, country                       [Finviz]                                                                               │
│     spectrum           spectrum of sectors, industry, country                          [Finviz]                                                                               │
│                                                                                                                                                                               │
│ Databases:                                                                                                                                                                    │
│     macro              collect macro data for a country or countries                   [EconDB]                                                                               │
│     treasury           obtain U.S. treasury rates                                      [EconDB]                                                                               │
│     fred               collect macro data from FRED based on a series ID               [FRED]                                                                                 │
│     index              find and plot any (major) index on the market                   [YahooFinance]                                                                         │
│                                                                                                                                                                               │
│ Stored datasets:                                                                                                                                                              │
│   macro        : france_GDP, germany_GDP, netherlands_GDP, france_TPOP_GDP, germany_TPOP_GDP, netherlands_TPOP_GDP                                                            │
│                                                                                                                                                                               │
│     eval               create new series by performing operations on loaded data                                                                                              │
│     plot               plot data from the above commands together                                                                                                             │
│                                                                                                                                                                               │
│ >   qa                 Open quantitative analysis menu with stored data                                                                                                       │
│                                                                                                                                                                               │
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I've also ensured it works well with plot.