Split C2A communication functions prototype declaration header

[sksat]

Related issues

N/A

Description

S2E has some C2A-interface for SILS-S2E; sometimes C2A's IfWrapper/HAL implementation calls S2E OBC_C2A functions like OBC_C2A_SendFromObc. These functions are defned in src/components/real/cdh/on_board_computer_with_c2a.hpp. However, it is unclear which functions are explicitly called by C2A. So, this PR change these declaration into another header file.

Impact

minor update

Supplementary information

N/A