Update ChangeLog for ECDSA contribution; clean up formatting

Signed-off-by: Josh Cepek <josh.cepek@usa.net>
Add Hacking docs

Signed-off-by: Josh Cepek <josh.cepek@usa.net>
Add Building info

Signed-off-by: Josh Cepek <josh.cepek@usa.net>
Add release-keys

The GPG/PGP keys listed in this file are used to sign official releases
of Easy-RSA 3. The keys themselves can be downloaded from the many
public keyserver mirrors.

Signed-off-by: Josh Cepek <josh.cepek@usa.net>
Update version strings to prepare for release tag v3.0.0-rc1

Signed-off-by: Josh Cepek <josh.cepek@usa.net>