Remove Flow

[stackptr]

Flow bindings are generated because projects downstream were not yet converted to TypeScript. Recently, the last project was migrated, so this generation should be removed.

[joris974]

Probably this could be done as well for all our JS libs:

• https://github.com/freckle/exhaustive-js
• https://github.com/freckle/parser-js
• https://github.com/freckle/maybe-js
• https://github.com/freckle/non-empty-js
• https://github.com/freckle/query-params-js
• https://github.com/freckle/resource-status-js