refactor(ops/modules): Move cgit configuration into a module

The ancient `//web/cgit-taz` path stems from the time I had
code.tazj.in serving my initial version of the depot.

I've been meaning to clean this up for forever, so here we go.

Note that this leaves the git-serving module in a strange state where
it only deals with josh. I'll rename it accordingly.

Change-Id: I47ed1e9d90958299b5440a18a1b9075274754e33
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5294
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: sterni <sternenseemann@systemli.org>

web/cgit-taz/default.nix

@@ -1,72 +0,0 @@
-# This derivation configures a 'cgit' instance to serve repositories
-# from a different source.
-{ depot, pkgs, ... }:
-
-let
-  inherit (pkgs)
-    mime-types
-    thttpd
-    writeShellScriptBin
-    writeText
-    ;
-
-  cgitConfig = writeText "cgitrc" ''
-    # Global configuration
-    virtual-root=/
-    enable-http-clone=0
-    readme=:README.md
-    about-filter=${depot.tools.cheddar.about-filter}/bin/cheddar-about
-    source-filter=${depot.tools.cheddar}/bin/cheddar
-    enable-log-filecount=1
-    enable-log-linecount=1
-    enable-follow-links=1
-    enable-blame=1
-    mimetype-file=${mime-types}/etc/mime.types
-    logo=https://static.tvl.fyi/${depot.web.static.drvHash}/logo-animated.svg
-
-    # Repository configuration
-    repo.url=depot
-    repo.path=/var/lib/gerrit/git/depot.git/
-    repo.desc=monorepo for the virus lounge
-    repo.owner=The Virus Lounge
-    repo.clone-url=https://code.tvl.fyi/depot.git
-  '';
-
-  thttpdConfig = writeText "thttpd.conf" ''
-    port=2448
-    dir=${depot.third_party.cgit}/cgit
-    nochroot
-    novhost
-    cgipat=**.cgi
-  '';
-
-  # Patched version of thttpd that serves cgit.cgi as the index and
-  # sets the environment variable for pointing cgit at the correct
-  # configuration.
-  #
-  # Things are done this way because recompilation of thttpd is much
-  # faster than cgit and I don't want to wait long when iterating on
-  # config.
-  thttpdConfigPatch = writeText "thttpd_cgit_conf.patch" ''
-    diff --git a/libhttpd.c b/libhttpd.c
-    index c6b1622..eef4b73 100644
-    --- a/libhttpd.c
-    +++ b/libhttpd.c
-    @@ -3055,4 +3055,6 @@ make_envp( httpd_conn* hc )
-
-         envn = 0;
-    +    // force cgit to load the correct configuration
-    +    envp[envn++] = "CGIT_CONFIG=${cgitConfig}";
-         envp[envn++] = build_env( "PATH=%s", CGI_PATH );
-     #ifdef CGI_LD_LIBRARY_PATH
-  '';
-  thttpdCgit = thttpd.overrideAttrs (old: {
-    patches = [
-      ./thttpd_cgi_idx.patch
-      thttpdConfigPatch
-    ];
-  });
-in
-writeShellScriptBin "cgit-launch" ''
-  exec ${thttpdCgit}/bin/thttpd -D -C ${thttpdConfig}
-''

web/cgit-taz/thttpd_cgi_idx.patch

@@ -1,13 +0,0 @@
-diff --git a/config.h b/config.h
-index 65ab1e3..cde470f 100644
---- a/config.h
-+++ b/config.h
-@@ -327,7 +327,7 @@
- /* CONFIGURE: A list of index filenames to check.  The files are searched
- ** for in this order.
- */
--#define INDEX_NAMES "index.html", "index.htm", "index.xhtml", "index.xht", "Default.htm", "index.cgi"
-+#define INDEX_NAMES "cgit.cgi"
- 
- /* CONFIGURE: If this is defined then thttpd will automatically generate
- ** index pages for directories that don't have an explicit index file.