HADOOP-18332: remove rs-api dependency as it conflicts with jsr311-api (#4547)

    This downgrades jackson from the version switched to in
    HADOOP-18033 (2.13.0), to Jackson 2.12.7.
    This removes the dependency on javax.ws.rs-api,
    so avoiding runtime problems with applications using
    jersey-core v1 and/or jsr311-api.
    
    The 2.12.7 release still contains the fix for CVE-2020-36518.
    
    Contributed by PJ Fanning
19 files changed