Root project documentation update

`README.md` is rework. Describe project concept description and
mention links. The old readme file build section move to the separate
file `BUILD.md`. It helps to fast read the corresponding file instead of
viewing a `README.md` table of content.

'CONTRIBUTING.md' file contents information to makes gain experience
and contribute in project easier.

'CHANGELOG.md' provide a detailed, chronological history of change
releases.

Signed-off-by: Alexey Gavrilov <alexey.gavrilov@mail.com>

0 files changed, 0 insertions, 0 deletions