iceoryx libs should be build as static libs

[dkroenke]

Required information

Operating system:
Ubuntu 18.04 LTS

Compiler version:
GCC 7.5.0

Observed result or behaviour:
When building the iceroyx lib and install them into build/install/prefix the application cannot find the .so files because LD_LIBRARY_PATH does not point to the custom location.
iox-roudi then throws the error:

bin/iox-roudi: error while loading shared libraries: libiceoryx_posh_config.so: cannot open shared object file: No such file or directory

output from ldd:

ldd bin/iox-roudi 
        linux-vdso.so.1 (0x00007fff1cf1d000)
        libiceoryx_posh_config.so => not found
        libiceoryx_posh_roudi.so => not found
        libiceoryx_posh.so => not found
        libiceoryx_utils.so => not found
        libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fb77124c000)
        libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fb77122f000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fb77103d000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fb770eee000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fb771474000)

Expected result or behaviour:
For better usability the default build should be a static lib to avoid setting the LD_LIBRARY_PATH manually.
The steps for using iceoryx as shared lib should be documented.

Conditions where it occurred / Performed steps:
Build iceoryx with build script and execute:

./build/install/prefix/bin/iox-roudi