Implement bar aggregation in Rust

[cjdsellers]

Implement BarAggregators and add to DataEngine.

[cjdsellers]

A decent base has been written.

Handing over to @faysou for now 🙏.

[faysou]

Yes, I'm working on this now, I have some bugs in tests I need to solve, should be ready some time this week.

[cjdsellers]

Closing this pending some further movement from @stastnypremysl

We can open more specific tickets when/if necessary.

Some aggregation methods still remain to be implemented per #2603.