Add interface to install certificate

An Interface to install the certificate provided by the user
and activate the services associated to the certificate.
README file provides the design details of uploading signed
certificate and private key and activating the new certificate.

Change-Id: Ib4e1ae2f957cce71698c2265bb733a04478b0abf
Signed-off-by: Jayanth Othayoth <ojayanth@in.ibm.com>
diff --git a/xyz/openbmc_project/Certs/Install.errors.yaml b/xyz/openbmc_project/Certs/Install.errors.yaml
new file mode 100644
index 0000000..5381de0
--- /dev/null
+++ b/xyz/openbmc_project/Certs/Install.errors.yaml
@@ -0,0 +1,3 @@
+# xyz.openbmc_project.Certs.Install.Error.InvalidCertificate
+ - name: InvalidCertificate
+   description: Invalid certificate file.