Generalized system clock call and error handler

[mcserved]

Summary:

This PR makes most (baremetal) applications use a single system clock configuration and error handler. These were previously included with the main.c. Related to #57.

Changes:

• New HAL clock file with standard clock configuration
• Replace all SystemClock_Config in baremetal applications (keeping ErrorHandler in the function, as it would produce warnings otherwise)
• Same two steps for Error_Handler
• Updated CMakeLists.txt for secure_element_lorawan and basic_bootloader as they did not include GNSE_HAL. STM32CubeIDE was already up-to-date on this.

Notes for Reviewers:

I excluded the RTOS applications as I think they are more suited with their own unique clock config and error handling method. Same for app_template.

One thing that could also be changed is that the error handler is used for the systemclock config. I wanted to replicate the functionality completely but maybe it is kinda out of place with the other function calls that also don't use the error handler,

[mcserved]

Reminder that the Error Handler would have to be updated when #205 is merged

[elsalahy]

@marnixcro this PR will be merged after #205, as 205 came first

[elsalahy]

@marnixcro Couldn't we just add the the error and CLK_Init functions under GNSE_hal.c instead of creating 4 more file to maintain. Do you see GNSE_clk.c or .h and GNSE_error.c or .h expanding in functionality?

[mcserved]

@marnixcro Couldn't we just add the the error and CLK_Init functions under GNSE_hal.c instead of creating 4 more file to maintain. Do you see GNSE_clk.c or .h and GNSE_error.c or .h expanding in functionality?

Good point, I'll update this