Create routers for period (non-lei checking) and institutions (lei checking)

[jcadam14]

Create a new Router in the regtech-api-commons repo that creates a router wrapper that has a dependency of verifying the user and lei association (see #102 ). So write a new story in that repo to create that. That way it other services need to do the same verification, they can all pull from the same Router.

Update the filing-api so that the /periods endpoint (and any future endpoints that don't need to check the user to lei association) use the non-checking router wrapper, and those that do (all the /institutions routes) use the new lei checker router.

This may be post-MVP, unless we have a little time to move things around, or see that we could benefit early from this change.