How to loop over this dictionary in Ansible?

Say I have this dictionary

war_files:
  server1:
  - file1.war
  - file2.war
  server2:
  - file1.war
  - file2.war
  - file3.war

and for now I just want to loop over each item (key), and then over each item in the key (value). I did this

- name: Loop over the dictionary
  debug: msg="Key={{ item.key }} value={{ item.value }}"
  with_dict: "{{ war_files }}"

And I get this. It is of course correct, but is NOT what I want.

ok: [localhost] => (item={'value': [u'file1.war', u'file2.war'], 'key': u'server1'}) => {
    "item": {
        "key": "server1", 
        "value": [
            "file1.war", 
            "file2.war"
        ]
    }, 
    "msg": "Server=server1, WAR=[u'file1.war', u'file2.war']"
}
ok: [localhost] => (item={'value': [u'file1.war', u'file2.war', u'file3.war'], 'key': u'server2'}) => {
    "item": {
        "key": "server2", 
        "value": [
            "file1.war", 
            "file2.war", 
            "file3.war"
        ]
    }, 
    "msg": "Server=server2, WAR=[u'file1.war', u'file2.war', u'file3.war']"
}

I want to get an output that says

"msg": "Server=server1, WAR=file1.war"
"msg": "Server=server1, WAR=file2.war"
"msg": "Server=server2, WAR=file1.war"
"msg": "Server=server2, WAR=file2.war"
"msg": "Server=server2, WAR=file3.war"

IOW, how can I write a task to iterates over the dictionary so it goes through each key, and then the items within each key? In essence, I have a nested array and want to iterate over it?

---

EDIT: At the time of writing this answer, Ansible 2.6 wasn't out. Please read the answer provided by @tmoschou, as it is much better.

---

Well, I couldn't find a very easy way to do it, however, with a little bit of jinja2, we can achieve something of this sort:

/tmp ❯❯❯ cat example.yml
---
- hosts: 127.0.0.1
  vars:
    war_files:
      server1:
      - file1.war
      - file2.war
      server2:
      - file1.war
      - file2.war
      - file3.war
  tasks:
  - set_fact:
      war_files_list_of_dicts: |
          {% set res = [] -%}
          {% for key in war_files.keys() -%}
             {% for value in war_files[key] -%}
              {% set ignored = res.extend([{'Server': key, 'WAR':value}]) -%}
             {%- endfor %}
          {%- endfor %}
          {{ res }}

  - name: let's debug the crap out of this
    debug: var=war_files_list_of_dicts

  - name: Servers and their WARs!!!
    debug:
       msg: "Server={{ item.Server }}, WAR={{ item.WAR }}"
    with_items: "{{ war_files_list_of_dicts }}"

And, when the playbook is run:

/tmp ❯❯❯ ansible-playbook example.yml
 [WARNING]: provided hosts list is empty, only localhost is available


PLAY [127.0.0.1] ***************************************************************

TASK [setup] *******************************************************************
ok: [127.0.0.1]

TASK [set_fact] ****************************************************************
ok: [127.0.0.1]

TASK [let's debug the crap out of this] ****************************************
ok: [127.0.0.1] => {
    "war_files_list_of_dicts": [
        {
            "Server": "server1", 
            "WAR": "file1.war"
        }, 
        {
            "Server": "server1", 
            "WAR": "file2.war"
        }, 
        {
            "Server": "server2", 
            "WAR": "file1.war"
        }, 
        {
            "Server": "server2", 
            "WAR": "file2.war"
        }, 
        {
            "Server": "server2", 
            "WAR": "file3.war"
        }
    ]
}

TASK [Servers and their WARs!!!] ***********************************************
ok: [127.0.0.1] => (item={'WAR': u'file1.war', 'Server': u'server1'}) => {
    "item": {
        "Server": "server1", 
        "WAR": "file1.war"
    }, 
    "msg": "Server=server1, WAR=file1.war"
}
ok: [127.0.0.1] => (item={'WAR': u'file2.war', 'Server': u'server1'}) => {
    "item": {
        "Server": "server1", 
        "WAR": "file2.war"
    }, 
    "msg": "Server=server1, WAR=file2.war"
}
ok: [127.0.0.1] => (item={'WAR': u'file1.war', 'Server': u'server2'}) => {
    "item": {
        "Server": "server2", 
        "WAR": "file1.war"
    }, 
    "msg": "Server=server2, WAR=file1.war"
}
ok: [127.0.0.1] => (item={'WAR': u'file2.war', 'Server': u'server2'}) => {
    "item": {
        "Server": "server2", 
        "WAR": "file2.war"
    }, 
    "msg": "Server=server2, WAR=file2.war"
}
ok: [127.0.0.1] => (item={'WAR': u'file3.war', 'Server': u'server2'}) => {
    "item": {
        "Server": "server2", 
        "WAR": "file3.war"
    }, 
    "msg": "Server=server2, WAR=file3.war"
}

PLAY RECAP *********************************************************************
127.0.0.1                  : ok=4    changed=0    unreachable=0    failed=0