chore: update test setup of e2e and integration

[jannisvisser]

Describe your changes

Resolves #1600 .

Checklist before requesting a review

• I have performed a self-review of my code
• I have added tests wherever relevant
• I have made sure that all automated checks pass before requesting a review

Notes for the reviewer

1. Any helpful instructions or clarifications...

[gulfaraz]

Add scripts for test:integration and test:e2e to the root package.json.

The tests pass,

> [email protected] test
> node --expose-gc ./node_modules/jest/bin/jest.js --config=jest.api.config.js --runInBand --detectOpenHandles --logHeapUsage

ts-jest[versions] (WARN) Version 4.9.5 of typescript installed has not been tested with ts-jest. If you're experiencing issues, consider using a supported version (>=2.7.0 <4.0.0). Please do not report issues in ts-jest if you are using unsupported versions.
 PASS  email/drought/email-uga-drought.test.ts (7.758s, 149 MB heap size)
  Should send an email for uga drought
    ✓ triggered in january (6768ms)

 PASS  email/floods/email-uga-floods.test.ts (32.35s, 146 MB heap size)
  Should send an email for uga floods
    ✓ trigger (8132ms)
    ✓ warning (7830ms)
    ✓ warning-to-trigger (8027ms)
    ✓ no-trigger (8221ms)

 PASS  email/floods/email-ssd-floods.test.ts (15.51s, 155 MB heap size)
  Should send an email for ssd floods
    ✓ trigger (7473ms)
    ✓ no-trigger (7930ms)

 PASS  email/flash-flood/email-mwi-flash-flood.test.ts (18.009s, 146 MB heap size)
  Should send an email for mwi flash flood
    ✓ trigger (9385ms)
    ✓ no-trigger (8484ms)

 PASS  email/malaria/email-eth-malaria.test.ts (18.972s, 156 MB heap size)
  Should send an email for eth malaria
    ✓ trigger (9674ms)
    ✓ no-trigger (9177ms)

 PASS  email/dengue/email-phl-dengue.test.ts (19.79s, 146 MB heap size)
  Should send an email for phl dengue
    ✓ trigger (9644ms)
    ✓ no-trigger (10025ms)

 PASS  email/typhoon/email-phl-typhoon.test.ts (12.815s, 150 MB heap size)
  Should send an email for phl typhoon
    ✓ trigger (12666ms)

Test Suites: 7 passed, 7 total
Tests:       14 passed, 14 total
Snapshots:   0 total
Time:        125.531s
Ran all test suites.