Adding option to configure compression level

Adding option to ota_from_target_files to configure compression level.
This option can be configured via the --vabc_compression_param flag.
e.g. --vabc_compression_param=gz,9 specifies gz compression algorithm
using level 9 compression

Test: ota_from_target_files
Change-Id: Ifc851faccbb3fba466d45c9695aaab322a362081