Migrate to linuxdeploy for building AppImages

AppImage recipes are the legacy method for building AppImages, whereas
linuxdeploy is meant to replace them. It takes care of finding and
deploying all needed libraries and Qt plugins automagically, but it's
still under heavy development, so some manual work using appimagetool
and a few fixes are required to make it work for KeePassXC.

This patch moves building of AppImages directly into the release-tool,
both as a separate module (release-tool appimage) as well as a flag
(--appimage) for the build module. The release and CI Dockerfiles were
updated accordingly to support the new build process. The release
Dockerfile also received a Qt update to version 5.10.1.

In theory, it is now possible to use release-tool appsign for embedding
PGP signatures into AppImages, but it fails in practice due to ELF
header size limitations.

Dockerfile

@@ -18,16 +18,16 @@ FROM ubuntu:14.04
 
 ENV REBUILD_COUNTER=8
 
-ENV QT5_VERSION=59
-ENV QT5_PPA_VERSION=${QT5_VERSION}4
+ENV QT5_VERSION=qt510
+ENV QT5_PPA_VERSION=qt-5.10.1
 ENV TERM=xterm-256color
 
 RUN set -x \
     && apt-get update -y \
     && apt-get -y install software-properties-common
 
 RUN set -x \
-    && add-apt-repository ppa:beineri/opt-qt${QT5_PPA_VERSION}-trusty \
+    && add-apt-repository ppa:beineri/opt-${QT5_PPA_VERSION}-trusty \
     && add-apt-repository ppa:phoerious/keepassxc
 
 RUN set -x \
@@ -38,39 +38,49 @@ RUN set -x \
 RUN set -x \
     && apt-get install -y \
         cmake3 \
+        curl \
         g++ \
         git \
         libgcrypt20-18-dev \
         libargon2-0-dev \
         libsodium-dev \
         libcurl-no-gcrypt-dev \
-        qt${QT5_VERSION}base \
-        qt${QT5_VERSION}tools \
-        qt${QT5_VERSION}x11extras \
-        qt${QT5_VERSION}translations \
-        qt${QT5_VERSION}imageformats \
+        ${QT5_VERSION}base \
+        ${QT5_VERSION}tools \
+        ${QT5_VERSION}x11extras \
+        ${QT5_VERSION}translations \
+        ${QT5_VERSION}imageformats \
         zlib1g-dev \
         libxi-dev \
         libxtst-dev \
         mesa-common-dev \
         libyubikey-dev \
         libykpers-1-dev
 
-ENV CMAKE_PREFIX_PATH="/opt/qt${QT5_VERSION}/lib/cmake"
+ENV PATH="/opt/${QT5_VERSION}/bin:${PATH}"
+ENV CMAKE_PREFIX_PATH="/opt/${QT5_VERSION}/lib/cmake"
 ENV CMAKE_INCLUDE_PATH="/opt/keepassxc-libs/include"
 ENV CMAKE_LIBRARY_PATH="/opt/keepassxc-libs/lib/x86_64-linux-gnu"
 ENV CPATH="${CMAKE_INCLUDE_PATH}"
-ENV LD_LIBRARY_PATH="${CMAKE_LIBRARY_PATH}:/opt/qt${QT5_VERSION}/lib"
+ENV LD_LIBRARY_PATH="${CMAKE_LIBRARY_PATH}:/opt/${QT5_VERSION}/lib"
 
 RUN set -x \
-    && echo "/opt/qt${QT5_VERSION}/lib" > /etc/ld.so.conf.d/qt${QT5_VERSION}.conf \
+    && echo "/opt/${QT5_VERSION}/lib" > /etc/ld.so.conf.d/${QT5_VERSION}.conf \
     && echo "/opt/keepassxc-libs/lib/x86_64-linux-gnu" > /etc/ld.so.conf.d/keepassxc.conf
 
 # AppImage dependencies
 RUN set -x \
     && apt-get install -y \
-        libfuse2 \
-        wget
+        curl \
+        libfuse2
+
+RUN set -x \
+    && curl -L "https://github.com/linuxdeploy/linuxdeploy/releases/download/continuous/linuxdeploy-x86_64.AppImage" > /usr/bin/linuxdeploy \
+    && curl -L "https://github.com/linuxdeploy/linuxdeploy-plugin-qt/releases/download/continuous/linuxdeploy-plugin-qt-x86_64.AppImage" > /usr/bin/linuxdeploy-plugin-qt \
+    && curl -L "https://github.com/AppImage/AppImageKit/releases/download/continuous/appimagetool-x86_64.AppImage" > /usr/bin/appimagetool \
+    && chmod +x /usr/bin/linuxdeploy \
+    && chmod +x /usr/bin/linuxdeploy-plugin-qt \
+    && chmod +x /usr/bin/appimagetool
 
 RUN set -x \
     && apt-get autoremove --purge \

ci/trusty/Dockerfile

@@ -20,7 +20,7 @@ FROM ubuntu:14.04
 
 ENV REBUILD_COUNTER=4
 
-ENV QT5_VERSION=53
+ENV QT5_VERSION=qt53
 ENV QT5_PPA_VERSION=${QT5_VERSION}2
 ENV TERM=xterm-256color
 
@@ -29,43 +29,58 @@ RUN set -x \
      && apt-get -y install software-properties-common
 
 RUN set -x \
-    && add-apt-repository ppa:beineri/opt-qt${QT5_PPA_VERSION}-trusty \
+    && add-apt-repository ppa:beineri/opt-${QT5_PPA_VERSION}-trusty \
     && add-apt-repository ppa:phoerious/keepassxc
 
 RUN set -x \
     && apt-get -y update \
     && apt-get -y --no-install-recommends install \
-      build-essential \
-      clang-3.6 \
-      libclang-common-3.6-dev \
-      clang-format-3.6 \
-      cmake3 \
-      make \
-      libgcrypt20-18-dev \
-      libargon2-0-dev \
-      libsodium-dev \
-      libcurl-no-gcrypt-dev \
-      qt${QT5_VERSION}base \
-      qt${QT5_VERSION}tools \
-      qt${QT5_VERSION}x11extras \
-      qt${QT5_VERSION}translations \
-      zlib1g-dev \
-      libyubikey-dev \
-      libykpers-1-dev \
-      libxi-dev \
-      libxtst-dev \
-      xvfb
+        build-essential \
+        clang-3.6 \
+        libclang-common-3.6-dev \
+        clang-format-3.6 \
+        cmake3 \
+        make \
+        libgcrypt20-18-dev \
+        libargon2-0-dev \
+        libsodium-dev \
+        libcurl-no-gcrypt-dev \
+        ${QT5_VERSION}base \
+        ${QT5_VERSION}tools \
+        ${QT5_VERSION}x11extras \
+        ${QT5_VERSION}translations \
+        zlib1g-dev \
+        libyubikey-dev \
+        libykpers-1-dev \
+        libxi-dev \
+        libxtst-dev \
+        xvfb
 
-ENV CMAKE_PREFIX_PATH="/opt/qt${QT5_VERSION}/lib/cmake"
+ENV PATH="/opt/${QT5_VERSION}/bin:${PATH}"
+ENV CMAKE_PREFIX_PATH="/opt/${QT5_VERSION}/lib/cmake"
 ENV CMAKE_INCLUDE_PATH="/opt/keepassxc-libs/include"
 ENV CMAKE_LIBRARY_PATH="/opt/keepassxc-libs/lib/x86_64-linux-gnu"
 ENV CPATH="${CMAKE_INCLUDE_PATH}"
-ENV LD_LIBRARY_PATH="${CMAKE_LIBRARY_PATH}:/opt/qt${QT5_VERSION}/lib"
+ENV LD_LIBRARY_PATH="${CMAKE_LIBRARY_PATH}:/opt/${QT5_VERSION}/lib"
 
 RUN set -x \
-    && echo "/opt/qt${QT5_VERSION}/lib" > /etc/ld.so.conf.d/qt${QT5_VERSION}.conf \
+    && echo "/opt/${QT5_VERSION}/lib" > /etc/ld.so.conf.d/${QT5_VERSION}.conf \
     && echo "/opt/keepassxc-libs/lib/x86_64-linux-gnu" > /etc/ld.so.conf.d/keepassxc.conf
 
+# AppImage dependencies
+RUN set -x \
+    && apt-get install -y \
+        curl \
+        libfuse2
+
+RUN set -x \
+    && curl -L "https://github.com/linuxdeploy/linuxdeploy/releases/download/continuous/linuxdeploy-x86_64.AppImage" > /usr/bin/linuxdeploy \
+    && curl -L "https://github.com/linuxdeploy/linuxdeploy-plugin-qt/releases/download/continuous/linuxdeploy-plugin-qt-x86_64.AppImage" > /usr/bin/linuxdeploy-plugin-qt \
+    && curl -L "https://github.com/AppImage/AppImageKit/releases/download/continuous/appimagetool-x86_64.AppImage" > /usr/bin/appimagetool \
+    && chmod +x /usr/bin/linuxdeploy \
+    && chmod +x /usr/bin/linuxdeploy-plugin-qt \
+    && chmod +x /usr/bin/appimagetool
+
 RUN set -x \
     && apt-get autoremove --purge \
     && rm -rf /var/lib/apt/lists/*