Filter to convert size for human readable usage

[renard]

Size such as disk or memory can now be converted to human readable
values in filters.

For example:

Variable is defined as:

sda_size: "{{ ansible_devices['sda'].sectors|int * ansible_devices['sda'].sectorsize|int }}"

This can be used:

• name: between 8Gb and 16Gb
  command: echo "{{ sda_size }}"
  when: sda_size|to_GiB <= 16 and sda_size|to_GiB > 8

New filters:

• to_KiB (binary unit 1024^1), to_KB (SI unit 1000^1)
• to_MiB (binary unit 1024^2), to_MB (SI unit 1000^2)
• to_GiB (binary unit 1024^3), to_GB (SI unit 1000^3)
• to_TiB (binary unit 1024^4), to_TB (SI unit 1000^4)

[amenonsen]

I like this feature quite a lot, the implementation is straightforward, and the merge conflict should be trivial to fix in devel, but there should be a couple of examples added to the documentation for it.

@renard, do you feel like resubmitting?

[bcoca]

actually, current devel has a human_readable filter already, closing this as it is already implemented