Add Grimmory subdomain config

[NaruZosa]

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• I have read the contributing guideline and understand that I have made the correct modifications

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Description

Adds a sample subdomain config for Grimmory.

Benefits of this PR and context

Grimmory is a maintained fork of Booklore, which had a sample config requested in #770

Please note that the Kobo integration docs specify Nginx requires the following settings:

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-Port $server_port;

proxy_buffer_size 128k;
proxy_buffers 4 256k;
proxy_busy_buffers_size 256k;
large_client_header_buffers 8 32k;

The sample config includes these, and is functional. When testing without these settings, syncing on my Kobo failed and SWAG logged the following error:
[error] 617761#617761: *7653 upstream sent too big header while reading response header from upstream, client: <REDACTED_IP>, server: grimmory.*, request: "GET /api/kobo/<REDACTED_API_TOKEN>/v1/library/sync?Filter=ALL&DownloadUrlFilter=Generic,Android&PrioritizeRecentReads=true HTTP/1.1", upstream: "http://<CONTAINER_IP>:6060/api/kobo/<REDACTED_API_TOKEN>/v1/library/sync?Filter=ALL&DownloadUrlFilter=Generic,Android&PrioritizeRecentReads=true", host: "grimmory.<REDACTED_DOMAIN>.com"

These settings conflict with /config/nginx/proxy.conf so the location /api/kobo/ does not include the line include /config/nginx/proxy.conf;.

How Has This Been Tested?

Tested and in active use on my instance, including the Kobo sync integration.

Source / References

[LinuxServer-CI]

This pull request has been automatically marked as stale because it has not had recent activity. This might be due to missing feedback from OP. It will be closed if no further activity occurs. Thank you for your contributions.

[NaruZosa]

Awaiting review.