Document nginx fastcgi_read_timeout setting for users of AMI ingesting from remote file systems

[patdunlavey]

As explored in this issue, AMI ingests of large media files from remote file systems (S3, in that case) can fail with a 504 gateway timeout error. This happens because the default nginx configuration is set with a fastcgi_read_timeout setting of 120 seconds, but it can take longer than that to fetch a very large media file, e.g. a movie.

The proposed solution is to document how to alter the nginx.conf in an appropriate place in the Archipelago documentation.

This task is to determine where this documentation should be created, and to create it.

[patdunlavey]

@DiegoPino or @alliomeria if you have thoughts about where this should be added to the documentation, assign this task to me and I'll write it.

[patdunlavey]

Perhaps as sub-bullet here?

[DiegoPino]

@patdunlavey, yes there (those docs are not meant for devops but would be great to mention, or even maybe a "troubleshooting" extra MD? @alliomeria? I would for sure also add it to archipelago-deployment-live docs (which sync automatically to archipelago documentation)