Description of problem:

ipauser module is not able to add gecos field:

~~~
- name: Playbook to handle users
  hosts: ipaserver
  become: true

  tasks:
  - ipauser:
      ipaadmin_password: '{{ ipaadmin_password }}'
      name: user1
      first: UserFirst
      last: UserLast
      phone: "+1234567890"
      email: user1
      password: "mypassword"
      gecos: UserFirst            <<<<<=====
      update_password: on_create
~~~
~~~
fatal: [<...>]: FAILED! => {"changed": false, "msg": "Unsupported parameters for (ipauser) module: gecos. Supported parameters include: phone (telephonenumber), nomembers, preserve, radius (ipatokenradiusconfiglink), userclass (class), mobile, manager, preferredlanguage, shell (loginshell), update_password, principalexpiration (krbprincipalexpiration), userauthtype (ipauserauthtype), title, userstate (st), noprivate, state, users, ipaadmin_password, name (login), passwordexpiration (krbpasswordexpiration), certificate (usercertificate), certmapdata, displayname, password, employeenumber, random, carlicense, ipaadmin_principal, radiususer (ipatokenradiususername, radiususername), last (sn), ipaapi_context, city, gid (gidnumber), homedir, email, departmentnumber, pager, uid (uidnumber), initials, employeetype, fax (facsimiletelephonenumber), sshpubkey (ipasshpubkey), first (givenname), action, principal (krbprincipalname, principalname), postalcode (zip), ipaapi_ldap_cache, orgunit (ou), fullname (cn)."}
~~~

The field is not in source code in v1.9.2 

https://github.com/freeipa/ansible-freeipa/blob/v1.9.2/plugins/modules/ipauser.py

-----

This field is supported in command line:

~~~
$ ipa user-add -h
Usage: ipa [global-options] user-add LOGIN [options]

Add a new user.
Options:
  -h, --help            show this help message and exit
  --first=STR           First name
  --last=STR            Last name
  --cn=STR              Full name
  --displayname=STR     Display name
  --initials=STR        Initials
  --homedir=STR         Home directory
  --gecos=STR           GECOS        <<<<<=====
  --shell=STR           Login shell
~~~