Add CI steps to web build scripts

Author: botder

tools/build_web.cmd

@@ -1,3 +1,7 @@
 @echo off
 
+if "%CI%" == "true" (
+    pip install -r web/requirements.txt
+)
+
 python web/wikigen.py build

tools/build_web.sh

@@ -1,3 +1,7 @@
 #!/bin/bash
 
+if [ "$CI" = "true" ]; then
+    pip install -r web/requirements.txt
+fi
+
 python web/wikigen.py build