[fixes #44711289] Expose TransferPlatesToPlates to API

Added transfer from 2 plates to 2 plates spec.
Need to add other tests to cover rack-to-rack,
rack-to-plate and plate-to-gel cases.
[fixes 44711289] Added more specs

Added specs to cover rack-to-rack,
rack-to-plate and plate-to-gel cases.
[fixes #44711289] correct syntax error

and remove duplicated shared contexts
[fixes #44711289] added the correct Gemfile
[#44711289] Add from multiply plates to 1 plate spec

Here plate means plate-like asset as plate, gel,
tuberack.
[fixes #44711289] fix plate_spec expected JSON's value
Use appropriate version of core.
Merge pull request #113 from maxigit/44711289_expose_transferplatestoplates_to_the_api

44711289 expose transferplatestoplates to the api