ARROW-16571: [Java] Update .gitignore to exclude JNI-related binaries

Adds three lines to gitignore to exclude three folders containing binaries and other build output produced by the JNI build process. The folders:
- java-dist/
- java-native-c/
- java-native-cpp/

are created in the root arrow directory when cmake is run

The command line build is documented here: https://arrow.apache.org/docs/dev/developers/java/building.html#

I followed the macOS instructions:

[Building JNI Libraries on MacOS](https://arrow.apache.org/docs/dev/developers/java/building.html#id7)

To build only the C Data Interface library:

    $ cd arrow
    $ brew bundle --file=cpp/Brewfile
    Homebrew Bundle complete! 25 Brewfile dependencies now installed.
    $ export JAVA_HOME=<absolute path to your java home>
    $ mkdir -p java-dist java-native-c
    $ cd java-native-c
    $ cmake \
        -DCMAKE_BUILD_TYPE=Release \
        -DCMAKE_INSTALL_LIBDIR=lib \
        -DCMAKE_INSTALL_PREFIX=../java-dist \
        ../java/c
    $ cmake --build . --target install

To build other JNI libraries:

    $ cd arrow
    $ brew bundle --file=cpp/Brewfile
    Homebrew Bundle complete! 25 Brewfile dependencies now installed.
    $ export JAVA_HOME=<absolute path to your java home>
    $ mkdir -p java-dist java-native-cpp
    $ cd java-native-cpp
    $ cmake \
        -DARROW_BOOST_USE_SHARED=OFF \
        -DARROW_BROTLI_USE_SHARED=OFF \
        -DARROW_BZ2_USE_SHARED=OFF \
        -DARROW_GFLAGS_USE_SHARED=OFF \
        -DARROW_GRPC_USE_SHARED=OFF \
        -DARROW_LZ4_USE_SHARED=OFF \
        -DARROW_OPENSSL_USE_SHARED=OFF \
        -DARROW_PROTOBUF_USE_SHARED=OFF \
        -DARROW_SNAPPY_USE_SHARED=OFF \
        -DARROW_THRIFT_USE_SHARED=OFF \
        -DARROW_UTF8PROC_USE_SHARED=OFF \
        -DARROW_ZSTD_USE_SHARED=OFF \
        -DARROW_JNI=ON \
        -DARROW_PARQUET=ON \
        -DARROW_FILESYSTEM=ON \
        -DARROW_DATASET=ON \
        -DARROW_GANDIVA_JAVA=ON \
        -DARROW_GANDIVA_STATIC_LIBSTDCPP=ON \
        -DARROW_GANDIVA=ON \
        -DARROW_ORC=ON \
        -DARROW_PLASMA_JAVA_CLIENT=ON \
        -DARROW_PLASMA=ON \
        -DCMAKE_BUILD_TYPE=Release \
        -DCMAKE_INSTALL_LIBDIR=lib \
        -DCMAKE_INSTALL_PREFIX=../java-dist \
        -DCMAKE_UNITY_BUILD=ON \
        -Dre2_SOURCE=BUNDLED \
        -DBoost_SOURCE=BUNDLED \
        -Dutf8proc_SOURCE=BUNDLED \
        -DSnappy_SOURCE=BUNDLED \
        -DORC_SOURCE=BUNDLED \
        -DZLIB_SOURCE=BUNDLED \
        ../cpp
    $ cmake --build . --target install

[Building Arrow JNI Modules](https://arrow.apache.org/docs/dev/developers/java/building.html#id8)

To compile the JNI bindings, use the arrow-c-data Maven profile:

    $ cd arrow/java
    $ mvn -Darrow.c.jni.dist.dir=../java-dist/lib -Parrow-c-data clean install

To compile the JNI bindings for ORC / Gandiva / Dataset, use the arrow-jni Maven profile:

    $ cd arrow/java
    $ mvn -Darrow.cpp.build.dir=../java-dist/lib -Parrow-jni clean install

Closes #13153 from lwhite1/update-gitignore-to-include-folders-where-binaries-are-created

Authored-by: Larry White <lwhite1@users.noreply.github.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>

Author: lwhite1

.gitignore

@@ -82,3 +82,8 @@ cpp/Brewfile.lock.json
 
 # docker volumes used for caching
 .docker
+
+# generated native binaries created by java JNI build
+java-dist/
+java-native-c/
+java-native-cpp/