docs: update build and sw requirement docs

    Updated build and software requirements documentation
    1. Simplified Linux and Windows build environment setup
    2. Updated tools version dependencies
    3. Removed some docs compilation warnings

Signed-off-by: Subhasish Ghosh <subhasish.ghosh@arm.com>
Change-Id: Ia0655e509d4a6424068b6113cc8a80f4b93fe8bd
3 files changed