Support of predefined kernel config by distributions and custom configs

**Is your feature request related to a problem? Please describe.**
- Many interesting Kernel modules and not always available as loadable modules and/or the default enabled modules are not always matching your specifics needs/regulatory requirements.
- Default kernel maintained in WSL is shared by all your WSL distribution instances
- Default kernel modules enabled by Microsoft does not match the ones enabled in distribution maintainers (e.g. MPTCP is enabled by default since Ubuntu 22.04 LTS, but not on WSL!)

**Describe the solution you'd like**
WSL3 could have a [cooperative mode](https://en.wikipedia.org/wiki/Cooperative_Linux) to provide a way to run simultaneously several kernel instances without relying to full VMs.

**Describe alternatives you've considered**
Providing a clean and easy way to compile a kernel version with predefined set (same as with orginal distros) and/or a custom kconfig - see https://github.com/microsoft/CBL-Mariner/issues/3550

No source files, tests, or entry points are identified in the issue. Start by reviewing the requested cooperative mode and the proposed predefined or custom kernel configuration, then define which approach is in scope and what support for distribution-specific modules would count as complete.

Written by the indexing model from the issue text.