meson: allow building resolved and machined without nss modules
    
    This adds -Dnss-resolve= and -Dnss-mymachines= meson options.
    By using this option, e.g., resolved can be built without nss-resolve.
    When no nss modules are built, then test-nss is neither built.
    
    Also, This changes the option name -Dmyhostname= to -Dnss-myhostname=
    for consistency to other nss related options.
    
    Closes #9596.
    
    (cherry picked from commit 08540a9591efe105439be81fc43d6dc65b715978)
    
    Resolves: #1696224
    
    patch_name: 0156-meson-allow-building-resolved-and-machined-without-n.patch
    present_in_specfile: true
    location_in_specfile: 156
    squash_commits: true