2nd try to add ZANavi to f-droid repo

i am new to f-droid build system, so be patient with me :-)

comments from last try:

• Commits should have been squashed

ok, how?

• Summary and metadata needs to be shrinked and be mre compliant with guidelines.

--> summary is shorter now. what else needs to be shrinked? can you point out the specific problem please?

• Build needs to be tested.

ok, tested locally with f-droid tools and works fine