Preserve the comments of the "cli.toml" on changes

[mamcx]

Description of Changes

We would like to preserve a user's manual edits, including comments, so now 'tolm_edit' is used for mutating the config file.

Closes #1798.

API and ABI breaking changes

Marked breaking because of the change of crate to parse and save. Is the low-level used by 'toml'.

Expected complexity level and risk

2:

Marked breaking because of the change of how to parse and save the file (that mutates instead of generating a fresh immutable view of the config) even if according to test there is none.

Testing

• Write unit testing that simulates different edits.
• Run 'standalone' and execute several 'cli' commands to see manually if the config was updated without issues.

[bfops]

left lots of nits, none of them critical

[gefjon]

Additional (manual) testing I would like to see done:

• Run multiple CLI processes concurrently / in parallel, such that they race to mutate a shared config file. Demonstrate that this does not corrupt or clear the config file, and describe the specific behavior.
• Manually create an ill-formed config file, run a CLI process that would mutate it, and demonstrate that the ill-formed file is not (further) corrupted or cleared. Describe the specific behavior.

[mamcx]

Additional (manual) testing I would like to see done:

• Run multiple CLI processes concurrently / in parallel, such that they race to mutate a shared config file. Demonstrate that this does not corrupt or clear the config file, and describe the specific behavior.
• Manually create an ill-formed config file, run a CLI process that would mutate it, and demonstrate that the ill-formed file is not (further) corrupted or cleared. Describe the specific behavior.

I added an automated test instead.

[bfops]

Thank you for addressing those comments!

[gefjon]

Looks great!