Make add/remove gridline function work properly#416

When using add gridlines to add sell orders to the bottom of a grid, the bot will not allow you to add sell orders unless there is base currency in the balance. However, if you have base currency available, the bot will not use it all and may convert quote currency into base to fill the additional gridlines.

This makes no sense.

1) Allow sell orders to be created with qvaialbel quote currency, in just the same way as when the bot is started you only need quote currency in your balance.
2) Allow all available base currency to be used. So long as 5% of quote is retained unused, there is no need for retaining any base in the available balance.

• If there is enough Base ccy, ie the required amount based on level $value, to add the sell grid lines then it gets used.
• Quote is required for buy (green) orders.

The overall required amounts for the modification is displayed to the user in the funds section

Additionally user can buy the required Base using the trading terminal