Generate Nginx includes for advanced configuration (e.g. SSL) (rebased onto metadata53)

[manics]

This is the same as gh-5381 but rebased onto metadata53.

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What this PR does

This creates a minimal nginx configuration file that can be included in a fixed file created by a sysadmin. This allows custom nginx options to be defined once (e.g. SSL options), instead of having to modify the generated web config after every upgrade, and means any Nginx server options can be used.

Testing this PR

1. Install a production OMERO.web in the standard way
2. Install Nginx.
3. Create a omero-web nginx wrapper file with an include statement for the generated omero-web config. This file is exclusively managed by the sysadmin e.g. /etc/nginx/conf.d/omero-web-wrapper.conf:

server {
    listen 80;
    server_name $hostname;

    # SSL configuration ...

    sendfile on;
    client_max_body_size 0;

    # Include generated file from omero web config nginx-location:
    include /opt/omero/web/omero-web-location.include;
}

4. Generate the minimal omero-web configuration in the location specified by your include statement. The expectation is that this would be routinely regenerated on every OMERO.web upgrade. e.g.

omero web config nginx-location > /opt/omero/web/omero-web-location.include

5. Start nginx
6. Start OMERO.web: omero web start
7. OMERO.web should work as normal

Related reading

• https://trello.com/c/igcRoPcu/11-configure-ssl-via-bin-omero-web-nginx

Notes

• omero web config nginx-location generates the location blocks only, other server options are now left for the sysadmin to manage e.g. sendfile on;, client_max_body_size 0;.
• I've removed the separate upstream block since there was only one server which means it's redundant, and it would be impossible to auto-generate a load-balanced upstream configuration since you'd need to know the addresses of all OMERO.web backends.

[manics]

--rebased-from #5381

[manics]

--rebased-to #5388

[joshmoore]

Merged to mainline.