Allow "none" or "baremetal" in framework selection for project creation

[maxgerhardt]

Per https://community.platformio.org/t/firmware-loaded-successfully-but-not-working-on-stm32/20362/7?u=maxgerhardt.

For platforms supporting bare-metal projects (and I think that's pretty much all of them), it would be nice to directly have this option in the list of frameworks, as e.g. "None" or "Bare-metal"

There should then be no framework = .. line in the platformio.ini and maybe a code template with an empty main() function.

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[maxgerhardt]

Push :)

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Please provide more details or it will be closed if no further activity occurs. Thank you for your contributions.

[maxgerhardt]

This is still valid.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Please provide more details or it will be closed if no further activity occurs. Thank you for your contributions.

[maxgerhardt]

This is still valid.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Please provide more details or it will be closed if no further activity occurs. Thank you for your contributions.

[maxgerhardt]

This issue is still valid.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Please provide more details or it will be closed if no further activity occurs. Thank you for your contributions.

[maxgerhardt]

This issue is still valid, number 5.