chore(general): configure sample-app deployment

[Den-dp]

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] The commit message follows our guidelines: https://github.com/datorama/akita/blob/master/CONTRIBUTING.md#commit
• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[x] CI related changes
[x] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: salesforce/akita#1052

What is the new behavior?

This PR enables CI to build and deploy ng-playground to akita.surge.sh

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

Requires specifying surge_login and surge_token env variables (can be obtained by running surge token)