OtaPreopt: Add version support

Add versioning to otapreopt:

Give up on having otapreopt being a mostly-ignorant frontend to a
blackbox dexopt function. Remove the dexopt helper taking a char*[], and
replace with a direct call to the typed signature.

Add support for a versioned dexopt command. The current version is
"2." An unversioned command string is either version "1" (N) or
version "2" (O pre-versioning).

Translate version 1 to version 2 by
* filter DEXOPT_OTA
* override dexopt_needed to DEX2OAT_FROM_SCRATCH
* add null se_info

Bug: 37256688
Test: m
Test: Manual OTA N (v1) -> O (v2)
Test: Manual OTA O (pre-versioning) -> O (v2)
Test: Manual OTA O (v2) -> O (v2)
Change-Id: I9fff673f3ba99833e88cf1c5c9625f42436ec150