Add decimal volume type and update trades, aggs and snapshot to use it.

[dhiaayachi]

Add support to decimal_volume, the volume including fractional shares volume.

[justinpolygon]

Hi @dhiaayachi, this is likely not needed in that I'm going to auto generate the client. I'm just flipping this over and will release a breaking change. So, you can just assign this linear task to me and I'll resolve it.

[dhiaayachi]

Hi @dhiaayachi, this is likely not needed in that I'm going to auto generate the client. I'm just flipping this over and will release a breaking change. So, you can just assign this linear task to me and I'll resolve it.

Thank you @justinpolygon for taking this! I will assign the ticket to you, just a heads up about the new field being a string. That was decided on purpose to allow conveying as much precision in the float as possible but we were thinking to provide some conveniency functions to do float conversion in the different libraries.