Change default election to 2020 for election search, senate candidate search

[lbeaufort]

User story: So that users can find information on the upcoming 2020 election, we should change default election to 2020 for the pages that default to the next upcoming election.

Election Search

https://www.fec.gov/data/elections/

Senate candidate data table

https://www.fec.gov/data/candidates/senate/

Keep to 2018

2-year financial period should stay defaulted to 2017-2018 until we get to the year-end deadline (1/31/19) because we don't have data for 2019-2020 yet, examples:

• House candidate search has no 2020 yet: https://www.fec.gov/data/candidates/house/

Candidate data table doesn't have a default https://www.fec.gov/data/candidates/?has_raised_funds=true

Completion criteria

• [x] Update Election Search to default to 2020
• [x] Update Senate candidate data table to default to 2020

[lbeaufort]

PR has been merged