Remove what is about deploying behind Gitea (closes #209)

Delete the Gitea compose setup, its document, its two scripts and their
make targets. Documents and tests no longer use Gitea as the example
deployment. The Core Rule Set exclusions for Gitea's false positives in
internal/waf stay, with their comments and tests.

Model: opus-5-5

docs/settings.md

@@ -101,19 +101,18 @@ chooses between the two (see "The image's command" below).
 
 - `SWWAF_RATE_LIMIT_PER_MINUTE` (default `120`, 2 a second): the most requests a
   client may make in a minute. A count or `off`. The default leaves room for a
-  person opening two gitea pages at once with an empty cache, up to 60 files
-  each.
+  person opening two pages at once with an empty cache, up to 60 files each.
 - `SWWAF_RATE_LIMIT_PER_HOUR` (default `1500`): the most requests a client may
   make in an hour. A count or `off`. It is the main limit against scrapers. A
-  person reading code in gitea for an hour, a page every 20 seconds, makes
-  about 900. A scraper making one request every 2 seconds makes 1,800 an hour,
-  more than the limit.
+  person reading a site for an hour, a page every 20 seconds, makes about 900. A
+  scraper making one request every 2 seconds makes 1,800 an hour, more than the
+  limit.
 - `SWWAF_RATE_LIMIT_PER_DAY` (default `6000`): the most requests a client may
   make in a day. A count or `off`. The default is four hours at the hour limit.
   A scraper making one request every 10 seconds makes 8,640 a day, more than the
   limit.
-- An Actions runner asks gitea for work all day and can pass the limits. Put the
-  runners' addresses in `SWWAF_RATE_LIMIT_EXEMPT_NETS`. Do the same for a
+- A CI runner asks its code forge for work all day and can pass the limits. Put
+  the runners' addresses in `SWWAF_RATE_LIMIT_EXEMPT_NETS`. Do the same for a
   network where many people share one address, such as an office.
 - Counting cannot catch a client that stays under all three limits (see "Request
   rate limits, per client" in [`SPEC.md`](../SPEC.md)).