[clean up] drop obsolete searx, filtron and morty install scripts

Since ./utils/searxng.sh is implemented, the old installation procedures from
filtron, morty and searx can be removed.

For users who want to upgrade, the procedures for removing old installations
have still been retained.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

.github/workflows/data-update.yml

@@ -26,7 +26,7 @@ jobs:
 
       - name: Install Ubuntu packages
         run: |
-          sudo ./utils/searx.sh install packages
+          sudo ./utils/searxng.sh install packages
 
       - name: Set up Python
         uses: actions/setup-python@v2

.github/workflows/integration.yml

@@ -19,7 +19,7 @@ jobs:
       uses: actions/checkout@v2
     - name: Install Ubuntu packages
       run: |
-        sudo ./utils/searx.sh install packages
+        sudo ./utils/searxng.sh install packages
         sudo apt install firefox
     - name: Set up Python
       uses: actions/setup-python@v2
@@ -55,7 +55,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Install Ubuntu packages
-      run: sudo ./utils/searx.sh install buildhost
+      run: sudo ./utils/searxng.sh install buildhost
     - name: Set up Python
       uses: actions/setup-python@v2
       with:
@@ -82,7 +82,7 @@ jobs:
         fetch-depth: '0'
         persist-credentials: false
     - name: Install Ubuntu packages
-      run: sudo ./utils/searx.sh install buildhost
+      run: sudo ./utils/searxng.sh install buildhost
     - name: Set up Python
       uses: actions/setup-python@v2
       with: