KTOR-7743 Create build-logic as a replacement for buildSrc

[osipxd]

Subsystem
Infrastructure

Motivation
It is the first step of refactoring build scripts to use precompiled script plugins (KTOR-7743).
Refactored build logic will be placed in the new build-logic module and at the end buildSrc will be completely removed.

Solution

• Create a new build-logic module
• Rename gradle-settings-conventions to build-settings-logic for consistency
• Add simple precompiled script plugins to demonstrate how it works