feat(file): add render command

[zekth]

Proposal of a new format for convert command. Possible things to address:

• Mocking the env variables
• compatibility with older kong versions

[codecov-commenter]

Codecov Report

Patch coverage: 21.31% and project coverage change: -0.08 ⚠️

Comparison is base (3184491) 35.59% compared to head (a964bb6) 35.52%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #874      +/-   ##
==========================================
- Coverage   35.59%   35.52%   -0.08%     
==========================================
  Files          92       92              
  Lines       11273    11309      +36     
==========================================
+ Hits         4013     4017       +4     
- Misses       6867     6897      +30     
- Partials      393      395       +2     

Impacted Files	Coverage Δ
cmd/convert.go	0.00% <0.00%> (ø)
convert/convert.go	74.26% <23.07%> (-15.10%)	⬇️
file/writer.go	14.86% <23.52%> (+0.32%)	⬆️

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[GGabriele]

TODO: add link to official Kong documentation here

[GGabriele]

@zekth it seems a test is failing due to some nil reference:

=== RUN   Test_Convert/converts_from_distributed_to_kong_gateway_(no_deck_specific_fields)
--- FAIL: Test_Convert (0.24s)
    --- PASS: Test_Convert/errors_out_due_to_invalid_conversion (0.03s)
    --- PASS: Test_Convert/errors_out_due_to_invalid_conversion#01 (0.02s)
    --- PASS: Test_Convert/errors_out_when_a_nameless_service_is_present_in_the_input (0.01s)
    --- PASS: Test_Convert/errors_out_when_input_file_doesn't_exist (0.00s)
    --- PASS: Test_Convert/converts_from_Kong_Gateway_to_Konnect_format (0.09s)
    --- PASS: Test_Convert/converts_from_Kong_Gateway_2.x_to_Kong_Gateway_3.x_format (0.04s)
    --- PASS: Test_Convert/converts_from_Kong_Gateway_2.x_to_Kong_Gateway_3.x_format_(no__format_version_input) (0.04s)
    --- FAIL: Test_Convert/converts_from_distributed_to_kong_gateway_(no_deck_specific_fields) (0.01s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xb421ef]

Would you mind checking?

[Tieske]

As per internal discussion, this functionality is to land in its own command "render", which is to be a subcommand of the new "file" command.

Since the "file" command is introduced in #939 , it makes sense to target that branch for now, instead of main.

[Tieske]

closing in favour of #963