Move to `std::vector` or similar and stop using VLAs

[peternewman]

In the future I think we should move to std::vector or similar. VLAs are not supported by some platforms (I think Windows is one of these?).

Originally posted by @DaAwesomeP in #2052 (comment)

[peternewman]

Current list, by looking for vla-cxx-extension in the clang logs include these:

2026-05-30T22:53:13.5636271Z ../../common/base/Init.cpp:210:23: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:53:13.5637723Z 210 | char *original_argv[original_argc];
2026-05-30T22:53:13.5638222Z | ^~~~~~~~~~~~~

2026-05-30T22:53:52.8160140Z ../../include/ola/strings/Utils.h:69:13: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:53:52.8160642Z 69 | char test[max_length + 1];
2026-05-30T22:53:52.8160890Z | ^~~~~~~~~~~~~~

2026-05-30T22:53:55.3174740Z ../../include/ola/rdm/ResponderSettings.h:274:9: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:53:55.3175382Z 274 | setting->DescriptionResponseSize()]; // NOLINT(runtime/arrays)
2026-05-30T22:53:55.3175759Z | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

2026-05-30T22:53:55.3182421Z ../../include/ola/rdm/ResponderSettings.h:274:9: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:53:55.3183254Z 274 | setting->DescriptionResponseSize()]; // NOLINT(runtime/arrays)
2026-05-30T22:53:55.3183794Z | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

2026-05-30T22:54:40.6711298Z ../../common/rdm/ResponderHelper.cpp:182:32: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:54:40.6712396Z 182 | uint16_t product_details_raw[product_details.size()];
2026-05-30T22:54:40.6713389Z | ^~~~~~~~~~~~~~~~~~~~~~

2026-05-30T22:54:40.6728418Z ../../common/rdm/ResponderHelper.cpp:318:29: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:54:40.6729491Z 318 | slot_info_s slot_info_raw[slot_data->SlotCount()];
2026-05-30T22:54:40.6730024Z | ^~~~~~~~~~~~~~~~~~~~~~

2026-05-30T22:54:40.6741254Z ../../common/rdm/ResponderHelper.cpp:410:35: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:54:40.6742442Z 410 | slot_default_s slot_default_raw[slot_data->SlotCount()];
2026-05-30T22:54:40.6743120Z | ^~~~~~~~~~~~~~~~~~~~~~

2026-05-30T22:54:40.6816290Z ../../common/rdm/ResponderHelper.cpp:683:37: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:54:40.6816915Z 683 | list_interfaces_s list_interfaces[interface_count];
2026-05-30T22:54:40.6817251Z | ^~~~~~~~~~~~~~~

2026-05-30T22:54:40.6887707Z ../../common/rdm/ResponderHelper.cpp:1087:24: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:54:40.6888704Z 1087 | uint8_t pattern_data[pattern_length];
2026-05-30T22:54:40.6888998Z | ^~~~~~~~~~~~~~

2026-05-30T22:54:40.6897756Z ../../common/rdm/ResponderHelper.cpp:1180:16: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:54:40.6898370Z 1180 | uint8_t tags[(MAX_RDM_STRING_LENGTH + 1) * tag_set->Size()];
2026-05-30T22:54:40.6898724Z | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

2026-05-30T22:56:15.6463455Z ../../olad/Olad.cpp:85:23: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:56:15.6464119Z 85 | char *original_argv[original_argc];
2026-05-30T22:56:15.6464400Z | ^~~~~~~~~~~~~

2026-05-30T22:59:06.3879177Z ../../plugins/milinst/MilInstWidget1463.cpp:93:15: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:59:06.3880211Z 93 | uint8_t msg[channels * 2];
2026-05-30T22:59:06.3880656Z | ^~~~~~~~~~~~

2026-05-30T22:59:07.6268398Z ../../plugins/milinst/MilInstWidget1553.cpp:153:15: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:59:07.6269259Z 153 | uint8_t msg[3 + channels];
2026-05-30T22:59:07.6270248Z | ^~~~~~~~~~~~

2026-05-30T22:59:46.8141484Z ../../plugins/renard/RenardWidget.cpp:143:15: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T22:59:46.8142557Z 143 | uint8_t msg[bufferSize];
2026-05-30T22:59:46.8143022Z | ^~~~~~~~~~

2026-05-30T23:01:10.6997399Z ../../plugins/usbdmx/VellemanK8062.cpp:207:26: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
2026-05-30T23:01:10.6998703Z 207 | unsigned char usb_data[m_chunk_size];
2026-05-30T23:01:10.6999222Z | ^~~~~~~~~~~~