Add functionality to the backtesting market and indicator graphs

[thetestspecimen]

Indicators can now be added to both the market graph and three independent indicator graphs below the market. The user can opt to have the indicators assigned automatically or have full control over where they are placed by using specific syntax when initialising the indicators in the strategy file for gekko.

The relevant adjustments are detailed below

• always display candlesticks for the market to avoid confusion with market indicators
• add three permanent indicator graphs below the market graph
• set market and three indicator graphs to fill screen vertically on a 1080p monitor
• set six groups with different ranges to cover all possible indicator ranges
• change market up to green and market down to red, as they were inverted in the candlestick chart
• add missing talib indicators to the indicators array
• make pattern indicators display on the market as a diamond marker with the name of the pattern above the diamond
• change location of buy and sell indicators on the market to be further away from the candles to stop interference
• add ability to specify which graph an indicator is displayed on
• add ability to auto-assign an indicator based on its absolute values
• update readme to give instructions on use of new features
• add new screenshots to readme and assets folder

[H256]

Hi @thetestspecimen - thanks for this wonderful contribution! I will test and review during the next week and then merge. ;)

[H256]

@thetestspecimen I have tested and found, that it doesn't work with most of the gekko native strategies (or any strategy that uses less than 3 indicators). Would you mind having a look at this again?

To reproduce - select RSI or MACD native strategy for example (both have only one indicator result per candle). It will not render the chart, giving the error

[Vue warn]: Error in mounted hook: "TypeError: options.xAxis[2] is undefined"

found in

---> <VueEchartWrapper> at src/components/global/chart.vue
       <QCardSection>
         <QCard>
           <Result> at src/components/backtester/result/result.vue
             <Backtester> at src/components/backtester/backtester.vue
               <QPage>
                 <BacktesterPage> at src/pages/backtest.vue
                   <QPageContainer>
                     <QLayout>
                       <MainLayoutPage> at src/layouts/default.vue
                         <App> at src/App.vue
                           <Root>

This is true for all other strategies using < 3 Indicators. All other things here look good to me.

[thetestspecimen]

Ok. No problem. I will take a look at this and get back to you.

I tend to use talib indicators rather than the gekko indicators. Although I did run through a few gekko indicators as a test and didn't hit a problem. We will see...

[H256]

Reviewed. Looks very good.