hidl_vec: move elements on resize

To avoid extra copies. Doing this also requires adding move
constructors and move assignment operators to hidl_array.

Bug: 135207394
Test: libhidl_test
Test: hidl_test
Test: reduces image size on aosp_walleye
$ cat installed-files-before.txt | awk '{s+=$1}END{print s}'
1135438223
$ cat installed-files-after.txt | awk '{s+=$1}END{print s}'
1135434327

Change-Id: I231f5c9cc959b605e6f102ff7217f338c95d5d5e
2 files changed