[FIX] hr_contract: Allow contract managers to manage employee

Contract managers should be able to create/manager employees.
This make sense when a contract manager hires someone.
He first creates the employee, then his contract.

This also allows contract managers to access private addresses
by transitivity.
This is also intended to allow a contract manager to set
a driver (private  partner) on the employee's company car
or to access `km_home_work` for transport reimbursment
(l10n_be_hr_payroll).

addons/hr_contract/security/security.xml

@@ -9,7 +9,7 @@
         <record id="hr_contract.group_hr_contract_manager" model="res.groups">
             <field name="name">Administrator</field>
             <field name="category_id" ref="base.module_category_human_resources_contracts"/>
-            <field name="implied_ids" eval="[(4, ref('base.group_user'))]"/>
+            <field name="implied_ids" eval="[(4, ref('base.group_user')), (4, ref('hr.group_hr_user'))]"/>
             <field name="users" eval="[(4, ref('base.user_root')), (4, ref('base.user_admin'))]"/>
         </record>