FEAT: Generate JNI headers

[KFilipek]

FEAT: Generate JNI headers during compilation process

Rationale

Principle: "avoid hardcoding".

Description

Now headers are hardcoded and placed in repository, but they should be generated automatically.

API Changes

N/A

Implementation details

1. Bump to Java 10 (javah executable is deprecated since Java 9 and removed in 10, so better is use newer version)
2. Use plugin to generate headers
3. Profit

Posts with explanation

$ cd pmemkv-binding/src/main/java
$ javah io.pmem.pmemkv.Database
$ ls
io  io_pmem_pmemkv_Database_Builder.h  io_pmem_pmemkv_Database.h

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