filesystem: revamp module (#2472)

* revamp filesystem module to prepare next steps

* pass all commands to module.run_command() as lists
* refactor grow() and grow_cmd() to not need to override them so much
* refactor all existing get_fs_size() overrides to raise a ValueError if
  not able to parse command output and return an integer.
* override MKFS_FORCE_FLAGS the same way for all fstypes that require it
* improve documentation of limitations of the module regarding FreeBSD
* fix indentation in DOCUMENTATION
* add/update function/method docstrings
* fix pylint hints

filesystem: refactor integration tests

* Include *reiserfs* and *swap* in tests.
* Fix reiserfs related code and tests accordingly.
* Replace "other fs" (unhandled by this module), from *swap* to *minix*
  (both mkswap and mkfs.minix being provided by util-linux).
* Replace *dd* commands by *filesize* dedicated module.
* Use FQCNs and name the tasks.
* Update main tests conditionals.

* add a changelog fragment

* Apply suggestions from code review

Co-authored-by: Felix Fontein <felix@fontein.de>

* declare variables as lists when lists are needed

* fix construction without useless conversion

Co-authored-by: Felix Fontein <felix@fontein.de>

tests/integration/targets/filesystem/tasks/create_device.yml

@@ -1,6 +1,9 @@
 ---
 - name: 'Create a "disk" file'
-  command: 'dd if=/dev/zero of={{ image_file }} bs=1M count={{ fssize }}'
+  community.general.filesize:
+    path: '{{ image_file }}'
+    size: '{{ fssize }}M'
+    force: true
 
 - vars:
     dev: '{{ image_file }}'
@@ -8,26 +11,29 @@
     - when: fstype == 'lvm'
       block:
         - name: 'Create a loop device for LVM'
-          command: 'losetup --show -f {{ dev }}'
+          ansible.builtin.command:
+            cmd: 'losetup --show -f {{ dev }}'
           register: loop_device_cmd
 
-        - set_fact:
+        - name: 'Switch to loop device target for further tasks'
+          ansible.builtin.set_fact:
             dev: "{{ loop_device_cmd.stdout }}"
 
     - include_tasks: '{{ action }}.yml'
 
   always:
     - name: 'Detach loop device used for LVM'
-      command: 'losetup -d {{ dev }}'
-      args:
+      ansible.builtin.command:
+        cmd: 'losetup -d {{ dev }}'
         removes: '{{ dev }}'
       when: fstype == 'lvm'
 
     - name: 'Clean correct device for LVM'
-      set_fact:
+      ansible.builtin.set_fact:
         dev: '{{ image_file }}'
       when: fstype == 'lvm'
 
-    - file:
+    - name: 'Remove disk image file'
+      ansible.builtin.file:
         name: '{{ image_file }}'
         state: absent