Add integration tests

This is to keep track of the current test additions. Before v0.1.0 release, we'd like to have the following tests first:

GET /stats/sequences/gentrap (for each gentrap summary examples)

• default arguments
• wrong libtype
• wrong seqqcphase
• nondefault libtype
• nondefault seqqcphase
• custom runIds
• custom refIds
• custom annotIds
• invalid runId
• invalid refId
• invalid annotIds

GET /stats/alignments/gentrap (for each gentrap summary examples)

• default arguments
• wrong libtype
• wrong accumulation level
• nondefault libtype
• nondefault accumulation level
• custom runIds
• custom refIds
• custom annotIds
• invalid runId
• invalid refId
• invalid annotIds

GET /stats/runs

• default arguments

GET /annotations

• default arguments

GET /annotations/:annotId

• default arguments
• nonexistent ID

GET /references

• default arguments

GET /references/:refId

• default arguments
• nonexistent ID

GET /users/:userId

• default arguments
• unauthenticated user
• unverified user
• unauthorized user

PATCH /users/:userId

• changing user ID not blocking for this release, so postponed indefinitely
• changing user API key not blocking for this release (also not the correct HTTP endpoint), postponed indefinitely
• changing password
• malformed patch
• empty patch
• unauthenticated user
• unverified user
• unauthorized user