CRM_Utils_Time - Prefer function names which match the stdlib counterparts

CRM_Utils_Time - Prefer function names which match the stdlib counterparts

There are a large number of calls to `time()`, `date()`, and `strtotime()`
in the codebase.  For someone doing a conversion, it's easier to understand
if the names match.

* Harder conversion
    * `time()` => `CRM_Utils_Time::getTimeRaw()`
    * `date()` => `CRM_Utils_Time::getTime()`
    * `strtotime()` => `strtotime(..., CRM_Utils_Time::getTimeRaw())`
* Easier conversion
    * `time()` => `CRM_Utils_Time::time()`
    * `date()` => `CRM_Utils_Time::date()`
    * `strtotime()` => `CRM_Utils_Time::strtotime()`