CMake: Don't force users to build specific library type

[rwalton-arm]

Description of defect

Ideally we wouldn't hardcode OBJECT, STATIC or shared libs. We should use default add_library calls where possible and let the consumer specify which type of lib to build.

There are a few blockers to implementing this:

• Mbed OS's use of weak linking
• Cyclic dependencies in Mbed OS modules

Target(s) affected by this defect ?

All

Toolchain(s) (name and version) displaying this defect ?

All

What version of Mbed-os are you using (tag or sha) ?

master

What version(s) of tools are you using. List all that apply (E.g. mbed-cli)

All

How is this defect reproduced ?

Build mbed-os

[ciarmcom]

Thank you for raising this detailed GitHub issue. I am now notifying our internal issue triagers.
Internal Jira reference: https://jira.arm.com/browse/IOTOSM-3779

[40Grit]

I still await a package management solution