Removing and renaming redundant tasks from Gradle

[Taher Alkhateeb]

Hello everyone,

I propose the following actions to update and cleanup build.gradle

- remove copyDtds (almost never used, and not related to building OFBiz)
- remove the "committerGroup" label
- change the group label for "svnInfoFooter" and "gitInfoFooter" to
"sysadminGroup"

WDYT