Facade OobDataMessage: Rename members to be generic.

Member names are LE specific when that isn't necessary.
Renaming as Classic now uses the same message too.

Bug: 162984360
Tag: #gd-refactor
Test: cert/run --host SecurityTest:test_successful_dut_initiated_ssp_oob
Test: cert/run --host LeSecurityTest
Change-Id: Ifd2c311a73d3e11cc64e287f18a5cb3e386e2f3c