GUACAMOLE-2139: Add automatic retrieval of license information where absent. Remove unused license info.

doc/licenses/slf4j-api/LICENSE.txt

@@ -2,9 +2,10 @@
 # URL:     http://slf4j.org/
 # From:    'QOS.ch Sàrl' (http://qos.ch/)
 # License: MIT
+# Source:  https://raw.githubusercontent.com/qos-ch/slf4j/refs/tags/v_${VERSION}/LICENSE.txt
 #
-# --- BEGIN LICENSE FILE ---
-Copyright (c) 2004-2024 QOS.ch Sarl (Switzerland)
+# --- BEGIN LICENSE FILE [2.0.17] ---
+Copyright (c) 2004-2022 QOS.ch Sarl (Switzerland)
 All rights reserved.
 
 Permission is hereby granted, free  of charge, to any person obtaining
@@ -25,4 +26,4 @@ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-# --- END LICENSE FILE ---
+# --- END LICENSE FILE [2.0.17] ---