FIO 7239: support for AWS S3 Multipart Upload

[brendanbond]

Link to Jira Ticket

https://formio.atlassian.net/browse/FIO-7239

Description

This PR

• adds support for AWS S3 multipart uploads to the File component edit form;
• adds support for AWS S3 multipart uploads to the S3 file storage provider;
• somewhat refactors the XHR submodule in the providers module to be more readable;
• converts provider functions from arrow functions into function statements so they're compatible with the TS build system;

Dependencies

formio-server:#1360

How has this PR been tested?

automated and manual testing

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (if applicable)
• My changes generate no new warnings
• My changes include tests that prove my fix is effective (or that my feature works as intended)
• New and existing unit/integration tests pass locally with my changes
• Any dependent changes have corresponding PRs that are listed above

[TanyaGashtold]

Looks good but please resolve the merge conflicts

[travist]

👍