Convert utils/httpRequestor.js to TypeScript

[markovic-smartsheet]

This one:

https://github.com/smartsheet/smartsheet-javascript-sdk/blob/mainline/lib/utils/httpRequestor.js

Acceptance Criteria:

• it compiles :)

[mattmeyerink]

Un-assigning myself from this ticket. We are going to wait to pick up the utils refactor until after the bulk of the typescript migration is complete.