Decompress S3 files without ".gz" extension

[fdartayre]

Describe a specific use case for the enhancement or feature:
Some files automatically generated by AWS are gzip compressed but named without a .gz extension.

Describe the enhancement:
Support for gzipped files in S3 input has been introduced in 7.5.0 (#13980) but as it relies on the .gz extension of the files, the S3 input doesn't decompress the files with a .gz extension. The request is to be able to decompress independently of the naming.

[elasticmachine]

Pinging @elastic/integrations-platforms (Team:Platforms)

[exekias]

I think this makes sense, we could do something like this:

Allow to configure a list of regexps to determine if decompression must be done, the default would be just \.gz$

[kaiyan-sheng]

Thank you @fdartayre for creating this issue!