[Proposal] Change list of mandatory parameters for rlm_sqlippool

[Geaaru]

Hi guys,

if I understood correctly configuration parameters inside rlm_sqlippool
with PW_TYPE_REQUIRED are needed because logic is related with a
classic SQL transaction but with some databases for examples
PostrgreSQL or Oracle logic could be reduce to a single procedure /
function that speedup interaction with database to a single call.

So, why not remove PW_TYPE_REQUIRED to allocate_clear, allocate_update
and/or others parameters?

A list of parameters where remove PW_TYPE_REQUIRED is:
- off_clear
- on_clear
- alive_update
- start_update
- allocate_update (allocate_find is sufficient)
- allocate_clear

User can be use it or not but is not a mandatory parameter and so it
could be do a choice about use it or not.

WDYT

G.