esp32c3: disable wdts in post_init

[MabezDev]

An exploration of something @jessebraham was looking into. This greatly simplifies the boilerplate for each example, by disabling the watchdogs before main. The watchdogs are enabled as a side effect of the ROM/second stage bootloader.

I probably won't finish this PR, but I hope it serves as a guide if someone wants to take on the rest of the chips :).

This will also require some changes in xtensa-lx-rt, to add __post_init support.

Thank you!

Thank you for your contribution.
Please make sure that your submission includes the following:

Must

• The code compiles without errors or warnings.
• All examples work.
• cargo fmt was run.
• Your changes were added to the CHANGELOG.md in the proper section.
• You updated existing examples or added examples (if applicable).
• Added examples are checked in CI

Nice to have

• You add a description of your work to this PR.
• You added proper docs for your newly added features and code.

[jessebraham]

I'm working on a follow-up to this

[jessebraham]

I've opened #763 which supersedes this, but thanks for this stepping stone!