Bump the dependency for KDevelop and Extragear to Qt 5.14 to reflect the fact that Plasma and parts of Applications (on which Extragear software depends) have bumped their dependency to Qt 5.14

Ref T12864

Libsodium is a high-level crypto library which is needed for Keysmith.

Example usage in CI scripts:

   /opt/helpers/build-autotools libsodium https://github.com/jedisct1/libsodium.git src/libsodium 1.0.18

The third argument is an optional branch/tag name to checkout.
It may also be left out in which case 'master' will be assumed by default.

Adopts Qt 5.14 which has several ramifications, biggest being Qt now
builds both arm32 and arm64 together. This merges both images back into
teh one which can produce all of the binaries.
It makes the image considerably bigger but doesn't make us have to use
two of them, which is helpful.

This also changes most of our tooling to produce both architectures per
run, it seems to work fine but more testing is needed.

For cmake we'll be just producing two separate prefixes. It's not ideal
but it works for now.

It can be used to validate GLSL shaders.

Ref T12721

This should enable support for newer versions of Frameworks.

Fixes T12704
Fixes T12701

Ref T12689

By default we only build the desktop one but let CI build both