Show UI warning to user when they need provider data but have not setup Synth yet

[zachgoll]

Simplify provider concerns

Previously, we had an abstract Providable implementation that given our sole usage of Synth, made working with provider data a bit confusing.

Now, all models that fetch external provider data will have a [Model]::Provided concern, which typically will expose a Model.provider class method. Now, working with the provider is a bit easier:

ExchangeRate.provider.present?
Security.provider.present?
Security::Price.provider.present?

If we add more providers in the future, the Model::Provided concern for each model will be responsible for configuring and choosing the desired provider for that type of data.

Add UI warning for Synth

If a family does not have Synth configured and meets any of the following criteria, we show a UI warning indicating that historical data is inaccurate.

• Has accounts not denominated in their Family currency
• Has investment trades
• Has entries not denominated in their Family currency