Add custom class codec via new QS_VALUE and QSerializerValue

[xor-gate]

See #21 for discussion. This is work in progress.

Small list of compatible changes:

• Add QS_VALUE macro for class property binding
• Add QSerializerValue abstract class for convenience of QS_VALUE class properties.
• Add Github Actions continuous integration workflow to auto-build/auto-run the code direct after change (on debian 13 Linux). See Checks (tab) in PR and Actions tab in the Repository
• Bumped upcomming v1.3 version

Semi-incompatible change(s):

• Did some project cleaning and restructuring

[xor-gate]

Hi @smurfomen , the PR is almost done, i still want to document the QSerializerValue abstract class methods. Let me know what you think of this addition and restructering.