Need configuration way to inject implementation of IScaleMetricsRepository

#### What problem would the feature you're requesting solve? Please describe.
We logicApps is an extention of FunctionApp.
IScaleMetricsRepository is an interface in Webjobs SDK.
FunctionApp injects an implementation of IScaleMetricsRepository, which is TableStorageScaleMetricsRepository.
We wanted to inject and replace the implementation of IScaleMetricsRepository with SqlStorageScaleMrtricsRepository in logic apps.

Currently it is not possible to do this.

#### Describe the solution you'd like
We need some configuration class through which we can add LogicApps version of IScaleMetricsRepository.

No files or tests are named. Start by tracing how FunctionApp injects TableStorageScaleMetricsRepository and how IScaleMetricsRepository is defined in the Webjobs SDK; compare the Logic Apps need for SqlStorageScaleMetricsRepository. Done means the host exposes a documented configuration path that allows this implementation to be replaced.

Written by the indexing model from the issue text.