Debian: Change debian files from stretch (Jetty 9.2, Tomcat 8, Java 8) to buster (Jetty 9.4, Tomcat 9, Java 11)

Add debian-alt/stretch files
Update debian-alt/precise, trusty, xenial, bionic, disco to include
 the changes from buster, not stretch
Remove debian-alt/buster, unstable files
Doc updates

debian/control

@@ -1,17 +1,19 @@
 Source: i2p
 Maintainer: zzz <zzz@i2pmail.org>
 Section: net
-Standards-Version: 3.9.8
+Standards-Version: 4.3.0
 Priority: optional
 Bugs: mailto:zzz@i2pmail.org
 Homepage: https://geti2p.net/
+Vcs-Browser: https://salsa.debian.org/debian/i2p
+Vcs-Git: https://salsa.debian.org/debian/i2p.git
 Build-Depends: debhelper (>= 9.20160709)
  ,ant (>= 1.8)
  ,debconf
- ,openjdk-8-jdk
+ ,default-jdk
  ,libjetty9-java
  ,libtaglibs-standard-jstlel-java
- ,libtomcat8-java
+ ,libtomcat9-java
  ,dh-apparmor
  ,bash-completion
  ,gettext
@@ -27,11 +29,13 @@ Section: net
 Priority: optional
 Depends: ${misc:Depends}, ${java:Depends}, ${shlibs:Depends},
  adduser,
+ apparmor,
  debconf,
  i2p-router (>= 0.8.6-5),
  libjbigi-jni,
  lsb-base,
- service-wrapper
+ service-wrapper,
+ ucf (>= 0.28)
 Description: Invisible Internet Project (I2P) - anonymous network
  I2P is an anonymizing network, offering a simple layer that identity-sensitive
  applications can use to securely communicate. All data is wrapped with several
@@ -74,15 +78,16 @@ Architecture: all
 Section: net
 Priority: optional
 Depends: ${misc:Depends}, ${java:Depends}, ${shlibs:Depends},
- openjdk-9-jre-headless | openjdk-8-jre-headless | default-jre-headless | java9-runtime-headless | java8-runtime-headless,
+ openjdk-11-jre-headless | java11-runtime-headless,
  geoip-database,
  gettext-base,
  libgetopt-java,
  libjson-simple-java (<< 3),
  libjetty9-java,
  libtaglibs-standard-jstlel-java,
- libtomcat8-java,
- famfamfam-flag-png
+ libtomcat9-java,
+ famfamfam-flag-png,
+ sensible-utils
 Replaces: i2p ( << 0.8.6-5)
 Breaks: i2p (<< 0.8.6-5)
 Recommends: libjbigi-jni, fonts-dejavu