#170301423 get expense endpoint

[Kasulejoseph]

What does this PR do?

• Allows passing limit as a query param

Description of Task to be completed

• When a limit param is not provided, Users can fetch all expenses. However, When limit param is provided, Users can only fetch the paginated items(by the passed limit)

How should this be manually tested?

-N/A

Any background context you want to provide?

-N/A

What are the relevant pivotal tracker stories?

#170301423

Screenshots (if appropriate)

NA