[508090] Fix: building the help makes the repository dirty

- Checked in all files generated with DITA 1.7.4, hoping to get rid of
unnecessary modifications to the generated files.
- add plugins to the gitignore file. It gets generated when the
documentation is built

Bug: 508090

Change-Id: I0b096dcf305874c852c1da4b71870595fde6bfe0
Signed-off-by: Krum Tsvetkov <krum.tsvetkov@sap.com>
13 files changed