Fix the Ruby warning about re-initializing the constant
Fix the Ruby warning about re-initializing the constant

We see the following warning from investapp:

    warning: already initialized constant Api::V3::ApiBuilderDefinitions::Shared::Pagination::DEFAULT_PER_PAGE
    (called from <module:Pagination> at app/controllers/api/v3/api_builder_definitions/shared/pagination.rb:9)
    previous definition of DEFAULT_PER_PAGE was here (called from <module:Pagination>
    at app/controllers/api/v3/api_builder_definitions/shared/pagination.rb:9)

This warning is from Ruby when we re-assign a constant, which often
happens when we use `load` instead of `require` to load a file.

The difference between `load` and `require` can be found here:
https://medium.com/@gooddb67/ruby-load-vs-require-vs-include-b6bf3c71e049

Also fixed the rubocop violation -- Lint/NonDeterministicRequireOrder

Cop doc:
https://docs.rubocop.org/rubocop/1.0/cops_lint.html#lintnondeterministicrequireorder

PR: https://github.com/sharesight/flappi/pull/49
Vimaly: https://vimaly.com/#j8mqm/t/SFxQqPYwAEa0CIc7g

sharesight/flappi,sharesight/flappi,sharesight/flappi