TT#12601 New column to store salted bcrypt hash

Storing salt and bcrypt hash per admin in this column.
Also clear existing ssl certs for security reasons. If someone
lost his key, it needs to be deleted and re-generated.

Change-Id: I0db91865f1ee248037bb0eaa31a97937c71d0ad6

db_scripts/diff/15325.down

@@ -0,0 +1,3 @@
+-- there is no down possibility here, as once active,
+-- we null out the old md5pass column with no way to
+-- return to the previous stage

db_scripts/diff/15325.up

@@ -0,0 +1,6 @@
+USE billing;
+
+ALTER TABLE admins ADD COLUMN saltedpass CHAR(54) DEFAULT NULL AFTER md5pass;
+
+-- clear all stored client certs
+UPDATE admins SET ssl_client_certificate = NULL;