[mod] simple theme: remove src/less/ion.less

This file is generated by webfont.
* It is now generated as searx/static/themes/simple/ion.less
* It is generated before the .less compilation.
* .gitignore includes this file

Add two new package depedencies: fontforge ttfautohint
See utils/searx.sh

.github/workflows/integration.yml

@@ -55,7 +55,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Install Ubuntu packages
-      run: sudo ./utils/searx.sh install packages
+      run: sudo ./utils/searx.sh install buildhost
     - name: Install node dependencies
       run: make V=1 node.env
     - name: Build themes