Standalone examples test install umf in user system, without user consent

[lplewa]

Standalone examples test:

• It fails in nominal environment (no permission to write to /usr/local)
• It install umf in user system. Without user consent and silently.
• And doesn't do a cleanup.

This is something we should not do.

If we want to test installation we should(select one):

• Do not run it as ctest command. Write separate test script which install and test umf and use it only in CI. (i.e as a part of the workflow we can have install step, and step to test standalone examples)
• Install umf to some temporary directory (inside build directory, or eventually in tmp directory). Use LD_LIBRARY_PATH to run tests.