Merge transfer stuses TS_TOSUBMIT into TS_PLANNED

The following discussion from !178 should be addressed:

• @bruno.carlin started a discussion: (+1 comment)

  Planned is already in the struct, but it is called Pending. You have 2 choices:

  1. keep Pending, and use that for Gateway
  2. rename it to Planned and change the R66 adapter so that it uses it correctly.

  Both are valid! It is your choice ;-)