Support ST chips with alternative internal flash configurations

[EkelmansPh]

Postmaster assumes a certain flash map is used to describe the internal flash configuration.
This is not valid for all ST controllers (i.e. STM32WB55).

amp-postmaster/postmaster/instantiations/TargetProgrammer.hpp

Line 61 in 9473c1d

std::array<uint32_t, 12> sectors{ 0x8000, 0x8000, 0x8000, 0x8000, 0x20000, 0x40000, 0x40000, 0x40000, 0x40000, 0x40000, 0x40000, 0x40000 };

Proposal would be to make this configurable through the postmaster API.
This could be done by making in configurable through the network headers.