Improve the README.md files by adding more details about
the PFDI specification and the implemented components.

Signed-off-by: Ziad Elhanafy <ziad.elhanafy@arm.com>

Update the README.md file to describe the platform fault
detection interface project, including libpfdi,
pfdi-sample-app, pfdi-cli and pfdi-tool.

Signed-off-by: Ziad Elhanafy <ziad.elhanafy@arm.com>
Signed-off-by: Divin Raj <divin.raj@arm.com>

Add a basic CI which runs a Danger job and essential codeclimate
checks.

Also add an introduction to the readme.md file.

Signed-off-by: Ziad Elhanafy <ziad.elhanafy@arm.com>