[server] Make connection pooler configurable and set better default values
Drop the configuration connections-pool-size and add new configurations options:
* connections-pool-min-size. Set to 0 by default so we open connections only
when needed. This avoid opening min-size*processes connections at startup,
which is, it think, a good default.
* connections-pool-max-size. Set to 0 (unlimited) by default, so we move the
bottleneck to postgresql.
* connections-idle-timeout. Set to 10 minutes. I don't have arguments about
this except that this is the default in pgbouncer.
Request and ResultSet methods
-----------------------------
Those are methods you'll find on both request objects and on
repository session.
Request methods
~~~~~~~~~~~~~~~
`URL handling`:
* `build_url(*args, **kwargs)`, returns an absolute URL based on the
given arguments. The *controller* supposed to handle the response,
can be specified through the first positional parameter (the
connection is theoretically done automatically :).
`Data formatting`:
* `format_date(date, date_format=None, time=False)` returns a string for a
date time according to instance's configuration
* `format_time(time)` returns a string for a date time according to
instance's configuration
`And more...`:
* `tal_render(template, variables)`, renders a precompiled page template with
variables in the given dictionary as context
Result set methods
~~~~~~~~~~~~~~~~~~
* `get_entity(row, col)`, returns the entity corresponding to the data position
in the *result set*
* `complete_entity(row, col, skip_bytes=True)`, is equivalent to `get_entity` but
also call the method `complete()` on the entity before returning it