Handle ill-formed dates, when requestimg Directors

[thorwolpert]

Describe the bug
A query string with an ill-formed date (eg. directors?date=2019-.3-21) raises an unhandled ValueError exception. It should be handled with a status=400 and an error message in the body

To Reproduce
curl
--compressed
-H "Accept: application/json, text/plain, /"
-H "Accept-Encoding: gzip, deflate, br"
-H "Accept-Language: en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7"
-H "Authorization: "
-H "Forwarded: for=184.66.237.20;host=legal-api-test.pathfinder.gov.bc.ca;proto=https;proto-version="
-H "Host: legal-api-test.pathfinder.gov.bc.ca"
-H "Origin: https://coops-test.pathfinder.gov.bc.ca"
-H "Referer: https://coops-test.pathfinder.gov.bc.ca/annual-report"
-H "Sec-Fetch-Mode: cors"
-H "Sec-Fetch-Site: same-site"
-H "User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"
-H "X-Forwarded-For: "
-H "X-Forwarded-Host: legal-api-test.pathfinder.gov.bc.ca"
-H "X-Forwarded-Port: 443"
-H "X-Forwarded-Proto: https"
"http://legal-api-test.pathfinder.gov.bc.ca/api/v1/businesses/CP0001254/directors?date=2019-.3-21"

Expected behavior
A clear and concise description of what you expected to happen.

Desktop (please complete the following information):

• OS: OSX - 10.13.6
• Browser: Chrome - 76.0.3809

Additional context
Sentry ticket - ENTITY-TEST-32