feat: add Price Oracles support

[khancode]

High Level Overview of Change

Add Price Oracles support - XRPLF/XRPL-Standards#129

Context of Change

Adds transactions: OracleSet, OracleDelete

Adds request: get_aggregate_price

Adds ledger entry: Oracle

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Tests (You added tests for code that already exists, or your new feature included in this PR)
• Documentation Updates
• Release

Did you update HISTORY.md?

• Yes
• No, this change does not impact library users

Test Plan

Adds unit/integration tests for Price Oracle transactions and request.

[mvadari]

Given the complexity of creating a price data object (with AssetPrice/Scale used to avoid floats), do you think it'd be useful to have a helper function to convert a float to AssetPrice/Scale (and vice versa)?

[mvadari]

It looks like the ledger_entry filter isn't updated for oracle here.

[khancode]

It looks like the ledger_entry filter isn't updated for oracle here.

But I included Oracle in the ledger entry filter. What's missing?

[khancode]

Given the complexity of creating a price data object (with AssetPrice/Scale used to avoid floats), do you think it'd be useful to have a helper function to convert a float to AssetPrice/Scale (and vice versa)?

I don't think it's necessary given the docs will explain this.

[khancode]

@mvadari I'm blocked on figuring out why the browser test fails. Any ideas?

[mvadari]

It looks like the ledger_entry filter isn't updated for oracle here.

But I included Oracle in the ledger entry filter. What's missing?

Missed that, sorry.

[mvadari]

Given the complexity of creating a price data object (with AssetPrice/Scale used to avoid floats), do you think it'd be useful to have a helper function to convert a float to AssetPrice/Scale (and vice versa)?

I don't think it's necessary given the docs will explain this.

I agree that the docs will explain this, but could be nice to have a helper function do the math for you. Not super important though.

[pdp2121]

LGTM