Files api v2

[atonks2]

This PR starts a new /v2/files/* API to introduce enhanced functionality without any breaking changes. The first new endpoint is a new version of the Create File endpoint.

In the current implementation, switching between ASCII and EBCDIC uploads requires a code change, which means new Docker image and deployment. The new version makes better use of Content-Type and Accept headers to support the following with no code or configuration updates:

• File creation via JSON payload
• Raw file upload via multipart/form-data request bodies
  • For now the only form section supported is file, but this approach will allow for easy additions in the future
• File format conversions:
  • Send JSON, receive ASCII or EBCDIC file download
  • Send raw file, receive JSON response
  • Send ASCII, receive EBCDIC
  • Send EBCDIC, receive ASCII

[codecov-commenter]

Codecov Report

Merging #345 (2d1df49) into master (9575bfd) will increase coverage by 10.07%.
The diff coverage is 73.33%.

❗ Current head 2d1df49 differs from pull request most recent head 8fc9513. Consider uploading reports for the commit 8fc9513 to get more accurate results

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Additional details and impacted files

@@             Coverage Diff             @@
##           master     #345       +/-   ##
===========================================
+ Coverage   74.08%   84.15%   +10.07%     
===========================================
  Files          41       39        -2     
  Lines        6034     5415      -619     
===========================================
+ Hits         4470     4557       +87     
+ Misses       1291      576      -715     
- Partials      273      282        +9