chore: rename mclogs filenames, asset paths, and runtime identifiers

Two file renames (docker/mclogs.ini -> docker/iblogs.ini,
web/public/css/mclogs.css -> web/public/css/iblogs.css) plus the
internal references that pointed at them (Dockerfile COPY directive,
the linux user name in the container).

Also catches the runtime identifier renames: env-var prefix MCLOGS_*
-> IBLOGS_* (compose files), browser cookie name MCLOGS_SETTINGS ->
IBLOGS_SETTINGS (web/public/js/log.js), production image tag
ghcr.io/aternosorg/mclogs:2 -> ghcr.io/indifferentketchup/iblogs:2,
and the README walk-through with the new branding.

example.config.json branding strings (legal contact, mclo.gs frontend
name) and visible UI text (taglines, meta descriptions) are deferred
to a separate branding commit.

web/public/js/log.js

@@ -203,7 +203,7 @@ function saveSettings() {
     for (const checkbox of settingCheckboxes) {
         data[checkbox.dataset.key] = checkbox.checked;
     }
-    document.cookie = "MCLOGS_SETTINGS=" + encodeURIComponent(JSON.stringify(data)) + ";path=/;expires=" + new Date(new Date().getTime() + 100 * 365 * 24 * 60 * 60 * 1000).toUTCString();
+    document.cookie = "IBLOGS_SETTINGS=" + encodeURIComponent(JSON.stringify(data)) + ";path=/;expires=" + new Date(new Date().getTime() + 100 * 365 * 24 * 60 * 60 * 1000).toUTCString();
 }
 
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