Create thick LV is broken

[stobbsm]

The current implementation has a default value of 100%FREE, but is using the -L|--size argument, which only allows physical sizes like 100G.

I would like to suggest changing the default -L 100%FREE to the more acceptable -l 100%FREE, which won't fail on run.
I'm not an ansible genius, but it should be possible to have different settings, ie. lvextentsize and lvbytesize, and to favour one over another.

Maybe set the default of lvextentsize, but if lvbytesize is defined, use that, which will be -L {SIZE}[M|G|T]