Checkout V2: Update authorization from Basic to Bearer

[sinourain]

Start sending requests using http Auth:Bearer

This PR was previously reviewed here, however after 60-days notice was automatically closed by AM, therefore I request a new review.

Spreedly reference:
OPPS-23

Remote:
Finished in 307.82125 seconds.
114 tests, 280 assertions, 2 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
98.2456% passed

Unit:
Finished in 41.256327 seconds.
6155 tests, 81007 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed
149.19 tests/s, 1963.50 assertions/s

RuboCop:
Inspecting 806 files
806 files inspected, no offenses detected

[sinourain]

I moved the PR to draft because in a test I get the error: processing_channel_id

[almalee24]

@sinourain theres a few failing remote tests

[sinourain]

@sinourain theres a few failing remote tests

The following tests were failing:

CASE A:

test_successful_purchase_with_processing_data

This test is still failing, the error code found in the official documentation is:

aft_processor_not_matched | Account funding transactions (AFTs) are not configured. A matching processor was not found.

CASE B: The following tests were deleted because they are meaningless with the latest NAS/HUB platform changes.
test_successful_purchase_for_secret_key_basic_authorization_header
test_money_transfer_payout_reverts_to_credit_if_payout_sent_as_nil
test_money_transfer_payout_handles_blank_destination_address

CASE C: Since payout and destination are now required in the options, it was added and this way the test no longer fails.
test_successful_credit