Switch to cmake + vcpkg, builds on linux, windows needs verification.

Code has been modified to be portable.

README.md

@@ -11,3 +11,41 @@ The release notes use collected from git using [reno](https://docs.openstack.org
 - googletest
 - libpq
 
+Boost, Botan, libpq and googletest are provided by vcpkg through the manifest in `vcpkg.json`, so you do not install them manually.
+
+## Required tools
+
+- CMake 3.21 or newer
+- A C++20 compiler (GCC or Clang on Linux, Visual Studio 2022 on Windows)
+- Qt 6 with the Core, Gui, Widgets, Sql and Concurrent components
+- vcpkg, with the `VCPKG_ROOT` environment variable pointing to its checkout
+- Ninja or make (optional, for faster builds)
+- A PostgreSQL server (only needed to run the application against a database)
+
+## Building
+
+Configure with the vcpkg toolchain file. The first configure downloads and builds the dependencies, which takes a while:
+
+```
+cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake
+cmake --build build
+```
+
+To skip the test executables, add `-DBUILD_TESTS=OFF` to the configure command.
+
+## Running the tests
+
+From the build directory, run:
+
+```
+ctest --output-on-failure
+```
+
+## Running the application
+
+The executable is built to `build/pglab/pglab`. On a machine without a display, set `QT_QPA_PLATFORM=offscreen`:
+
+```
+./build/pglab/pglab
+```
+