Addition of Cypress for E2E testing

[goran-peoski-work]

Partially resolves:

• https://github.com/sparkletown/internal-sparkle-issues/issues/1821

This is just the first inclusion, should work by manually invoking:

• npm run firebase:emulate-cy:run - to test the stub of first two specs
• npm run firebase:emulate-cy:open - to have a "development" version of Cypress for writing more specs
• npm run firebase:emulate-cy:prepare - for rare occasions where changes to the DB seed need to be persisted for future tests

Parts of the chain can be run separately, like npm run cy:open or npm run firebase:emulate-cy, but in general they serve as a components for a more complex pipelines like in CircleCI and/or locally through husky triggers for git actions (done by follow up PRs).

One more thing to be added with follow up PR is the ability to reset auth and/or users, similar to the Firestore DB utilities added in this PR.

[UPDATE] A CircleCI related sub-PR has been merged to this one that allows for the CI workflow to trigger the end-to-end tests automatically:

• https://github.com/sparkletown/sparkle/pull/3064

Here is how the CLI output of a run looks like:

Here are the videos recorded by the specs themselves during their runs:

https://user-images.githubusercontent.com/79229621/165724278-630380b5-251a-4a7e-bdc9-54738aedfdee.mp4

https://user-images.githubusercontent.com/79229621/165724292-4c2816aa-2aab-48b4-b296-f68f20f2ba0e.mp4