monitoring01: remove host and migrate services to monitoring02

Remove monitoring01 host configuration and unused service modules
(prometheus, grafana, loki, tempo, pyroscope). Migrate blackbox,
exportarr, and pve exporters to monitoring02 with scrape configs
moved to VictoriaMetrics. Update alert rules, terraform vault
policies/secrets, http-proxy entries, and documentation to reflect
the monitoring02 migration.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

flake.nix

@@ -92,15 +92,6 @@
             ./hosts/http-proxy
           ];
         };
-        monitoring01 = nixpkgs.lib.nixosSystem {
-          inherit system;
-          specialArgs = {
-            inherit inputs self;
-          };
-          modules = commonModules ++ [
-            ./hosts/monitoring01
-          ];
-        };
         jelly01 = nixpkgs.lib.nixosSystem {
           inherit system;
           specialArgs = {