Replace buildSrc plugins with composite build

[Chrylo]

Is your feature request related to a problem? Please describe.
#45 #71 added the first composite build into the project. This adds a limitation to reuse the plugins defined in the buildSrc folder of the root SDK project leading to redundant code or missing functionality e.g. Detekt / KTlint are not active for the vss-processor-plugin module.

Describe the solution you'd like
Moving all reusable plugins defined in the buildSrc folder to a composite plugin module will make the plugins reusable to all modules in the project.

Additional context
Reference: https://medium.com/bumble-tech/how-to-use-composite-builds-as-a-replacement-of-buildsrc-in-gradle-64ff99344b58