* Load plugins only if they are required
This reduce a lot starting time of Rally and will
allows us to do online bash completition
As well it cleans up project structure a lot, e.g.
all plugins are loaded in single place +
we don't have strange code in cliutils
* Replace rally.ui.utils to not import mako
and remove all code on module level
* Make Rally DB lazy inited
* Import plugins during test run
----
The best way to test changes in start up time is to
compare "time rally version" e.g.:
before this patch:
$ time rally version
0.0.5
real 0m0.397s
user 0m0.299s
sys 0m0.089s
after this patch:
0.0.5
real 0m0.281s
user 0m0.200s
sys 0m0.077s
Change-Id: Ibec2e6da66a1304730e801de307df7a1da68d51f
d3773cbfbe