Added Form Validation rule for alphanum + spaces.

Signed-off-by: Sajan Parikh <sajan@noppix.com>
Fixed documentation.

Signed-off-by: Sajan Parikh <sajan@noppix.com>
Added error message in lang file.

Signed-off-by: Sajan Parikh <sajan@noppix.com>
Cleaned up for pull request.

Signed-off-by: Sajan Parikh <sajan@noppix.com>
Add entry in user guide changelog.

Signed-off-by: Sajan Parikh <sajan@noppix.com>
Merge pull request #2220 from sajanNOPPIX/develop

New Form Validation Rule: alpha_numeric_spaces