The HttpRequest.{h,cpp}.mustache files contain code for compressing and decompressing data using zlib.

This code is controlled by the {{#contentCompression}} flag, which is by default turned off.

The scope of this task is to create new tests with enabled compression in the generator and make sure that everything builds and works correctly.

This might require changes in CMakeLists.txt.mustache, and also in the code of HttpRequestWorker::compress() and HttpRequestWorker::decompress() methods.

At first glance I can identify the following issues:

• CMakeLists.txt tries to link to ${ZLIB_LIBRARIES}, but misses the call to FindZLIB().
• The compression and decompression code uses int to represent the size of QByteArray. We need to change it to qsizetype and make sure that there's no overflow when working with > 2 GiB data.
• ...