Add Arabic translations.
merged branch mahmouds/arabic-support-master (PR #6944)

This PR was submitted for the master branch but it was merged into the 2.2 branch instead (closes #6944).

Commits
-------

2b850b5 [Form] [Validator] [Security] Add Arabic translations.

Discussion
----------

[Form] [Validator] [Security] Add Arabic translations.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | ~
| License       | MIT
| Doc PR        | ~