[LLVM] - Update the documentation to suggest building dependencies as shared libraries instead of static libraries for individual contributors

As I was working on an issue, the build used to break consistently due to lack of RAM memory at building time. To deal with it, I increased my RAM to 64GBs and the final target still failed to build due to RAM getting full. I added the flag -DBUILD_SHARED_LIBS=ON .
Specially for new contributors like myself, not paying attention to this can lead to a very frustrating attempt and hinders the development's velocity.
I suggest adding this as a suggestion to the user-guide documents on LLVM repo. I can do it myself if it approved as an issue to be worked on.

Start by searching the LLVM user-guide documents for dependency or build instructions related to BUILD_SHARED_LIBS. Update the relevant guidance to suggest shared libraries for individual contributors, then check the documentation formatting and build instructions to confirm the change is complete.

Written by the indexing model from the issue text.