[FEATURE] Allow generated output to be placed relative to other rules

[alexlo03]

Is your feature request related to a problem? Please describe.
I am unable to get the CODEOWNERS output to be ordered. Since order determines rule precedence, it is something I need in order to use this solution. For example I may have a super rule that is like **/special.yaml is only editable by maintainers no matter where it is in the repo. I can do this by putting it at the bottom of the CODEOWNERS file.

Describe the solution you'd like
Presently the codeowners-generator wants to put its output at the BOTTOM of the CODEOWNERS file. I would like it to look for "# GENERATE_CODEOWNERS_HERE" and place the block there if it exists.

I would place that token in the middle of my existing CODEOWNERS file, because the bottom rules are important and need to take precedence.

Describe alternatives you've considered
I may be able to do this with the "run after" script, but it seems possible to do this as a first class feature.

Additional context
Maybe I missed a better way to do this? If so, apologies!

[gagoar]

thank you @alexlo03 for your request!

Sounds very doable actually. To summarize:
add an option to keep the block where it starts (and is in the file already).

That's something we can do. I will have to add an option like preserve-position or something like that.

[gagoar]

Just an update: I've finished the implementation here. I'm waiting for @gustavkj second pair of eyes. Feel free to review if Ts is your thing!