new feature: users are now able to provide more file types to convert by adding entries in their configuration file

[gulien]

This PR implements a solution for allowing users to provide more / less file types to convert by adding / removing entries in their configuration file.

New gotenberg.yml format:

# The port the application will listen to.
port: 3000

logs:
  # Accepted values, in order of severity: DEBUG, INFO, WARN, ERROR, FATAL, PANIC.
  # Messages at and above the selected level will be logged.
  level: "DEBUG"

  # Accepted values: text, json.
  # When a TTY is not attached, the output will be in the defined format.
  formatter: "text"

# You don't like a library which is used for a conversion? You want to handle a new file type?
# You may provide here your own implementation!
commands:

  # Unlike others commands' templates, you have access to FilesPaths instead of FilePath: it gathers all PDF files which should be merged.
  merge:
    template: "pdftk {{ range $filePath := .FilesPaths }} {{ $filePath }} {{ end }} cat output {{ .ResultFilePath }}"
    timeout: 30
  
  conversions:

      # The command template: you have access to FilePath and ResultFilePath variables.
    - template: "markdown-pdf {{ .FilePath }} -o {{ .ResultFilePath }}"
      # Duration in seconds after which the command will be killed if it has not finished.
      timeout: 30
      # Files with the following extensions will be converted by the current command.
      extensions:
        - ".md"

    - template: "xvfb-run -e /dev/stdout wkhtmltopdf {{ .FilePath }} {{ .ResultFilePath }}"
      timeout: 30
      extensions:
        - ".html"
        - ".htm"

    - template: "unoconv --format pdf --output \"{{ .ResultFilePath }}\" \"{{ .FilePath }}\""
      timeout: 30
      extensions:
        - ".doc"
        - ".docx"
        - ".odt"
        - ".xls"
        - ".xlsx"
        - ".ods"
        - ".ppt"
        - ".pptx"
        - ".odp"

Checklist

• Have you followed the guidelines in our CONTRIBUTING guide?
• Have you lint your code locally prior to submission (orbit run fmt)?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally (orbit run ci)?
• I have squashed any insignificant commits
• This change has comments for package types, values, functions, and non-obvious lines of code

[codecov]

Codecov Report

Merging #3 into master will decrease coverage by 1.16%.
The diff coverage is 94.31%.

@@            Coverage Diff             @@
##           master       #3      +/-   ##
==========================================
- Coverage   92.04%   90.87%   -1.17%     
==========================================
  Files           7        8       +1     
  Lines         327      307      -20     
==========================================
- Hits          301      279      -22     
- Misses         15       16       +1     
- Partials       11       12       +1

Impacted Files	Coverage Δ
app/http/http.go	100% <ø> (ø)	⬆️
app/converter/file/file.go	77.77% <100%> (-3.18%)	⬇️
app/converter/converter.go	90.47% <100%> (ø)	⬆️
app/config/config.go	100% <100%> (ø)	⬆️
app/config/parser.go	100% <100%> (ø)
app/converter/process/process.go	80.39% <50%> (-8.18%)	⬇️

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