Add full name to account and use it to create commits (#125)

The Git practice is to use the full name when creating commits, not a
user name. This commit fixes that by introducing a fullName field to
Account and using it when creating commits.

For migrating from earlier versions, the user name is used as an initial
value for the full name field.

src/main/resources/update/1_7.sql

@@ -0,0 +1,5 @@
+ALTER TABLE ACCOUNT ADD COLUMN FULL_NAME VARCHAR(100);
+
+UPDATE ACCOUNT SET FULL_NAME = USER_NAME WHERE FULL_NAME IS NULL;
+
+ALTER TABLE ACCOUNT ALTER COLUMN FULL_NAME SET NOT NULL;