Feat: Implement ipfs swarm limit [scope] --reset

[Ghvstcode]

Hey there,
This PR adds support for resetting custom limits by scope to implicit defaults.

Closes #8918!
———
Summary

• Add an optional reset flag to enable resetting to default
• Persist default settings without node restart

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[Ghvstcode]

Hi @guseggert, @lidel

[BigLep]

@schomatis : can you take this PR please? I believe the related issue has the important context.

[BigLep]

@schomatis : if there are followup questions, @guseggert can help.

[Jorropo]

It solves issue #8918!

Not related on the code at all.
Just FYI, when you do this kind of stuff pls use a syntax github understands like:

Closes #8918

or

Fixes #8918

Also pls add this as it's own paragraph.
(we usually put it at the end but I don't have any preference)

Then github will wire "may be fixed messages" and automatically close the issue if this gets merged. 🙂

[schomatis]

Ack, will review next week.

@Ghvstcode Thanks for the patch. We're likely going to need a test for this command in sharness. If you're not familiar with it could you write here an example run of your command and what output you'd expect, please? Without any context on this I'm assuming it'd be something like:

ipfs swarm limit <set a limit that it's not the default>
ipfs swarm limit --reset
ipfs swarm limit
# Check that it matches default.

# (and probably a similar one with a scope set that resets only that one and not the rest)

(Basically your command and the expected output in a couple of typical use cases.)

[schomatis]

For more background the other rcmgr tests are in:

https://github.com/ipfs/go-ipfs/blob/master/test/sharness/t0139-swarm-rcmgr.sh.

[schomatis]

Why do we need this?