New fee limit defaults and behavior

[kaloudis]

Description

This PR makes two changes to how fee limits for LN payments work in ZEUS:

1. The default values are changed:

• Fee limit fixed: 100 sats -> 1000 sats
• Fee limit percentage: 0.5% -> 5%
• Fee limit method setting is effectively removed

2. The default fee limit method logic has been changed.

Previously: the method (percentage or fixed) would be chosen based on what the user had in their settings (default: fixed) - regardless of the payment size.
Now: Fee limit method will default to fixed for amounts up to 1000 sats and percentage for amounts greater than 1000 sats. You'll be able to change which method and values to use though, under the Settings section of the Payment Request view.

New explainer has been added to the Payment settings view:

This pull request is categorized as a:

• New feature
• Bug fix
• Code refactor
• Configuration change
• Locales update
• Quality assurance
• Other

Checklist

• I’ve run yarn run tsc and made sure my code compiles correctly
• I’ve run yarn run lint and made sure my code didn’t contain any problematic patterns
• I’ve run yarn run prettier and made sure my code is formatted correctly
• I’ve run yarn run test and made sure all of the tests pass

Testing

If you modified or added a utility file, did you add new unit tests?

• No, I’m a fool
• Yes
• N/A

I have tested this PR on the following platforms (please specify OS version and phone model/VM):

• Android
• iOS

I have tested this PR with the following types of nodes (please specify node version and API version where appropriate):

• Embedded LND
• LND (REST)
• LND (Lightning Node Connect)
• Core Lightning (c-lightning-REST)
• LndHub
• [DEPRECATED] Core Lightning (Spark)
• [DEPRECATED] Eclair

Locales

• I’ve added new locale text that requires translations
• I’m aware that new translations should be made on the ZEUS Transfix page and not directly to this repo

Third Party Dependencies and Packages

• Contributors will need to run yarn after this PR is merged in
• 3rd party dependencies have been modified:
  • verify that package.json and yarn.lock have been properly updated
  • verify that dependencies are installed for both iOS and Android platforms

Other:

• Changes were made that require an update to the README
• Changes were made that require an update to onboarding

[bedair81]

Like and support this change👍🏻

[myxmaster]

Not sure if I understand correctly, but this seems weird to me.

For amounts up to 1,000 sats, Zeus will allow paying fees up to 1,000 sats?
-> User pays e.g. 1 sat and can pay up to 1,000 sats fee. And when you send more than 1,000 sats it is limited to 5%.

That would mean:

sending amount	max fee	max fee %
1 sat	1,000 sats	100,000%
10 sats	1,000 sats	10,000%
100 sats	1,000 sats	1,000%
1,000 sats	1,000 sats	100%
above 1,000 sats		5%

[kaloudis]

@myxmaster what if we limit the low amounts to 100%

[myxmaster]

what if we limit the low amounts to 100%

That is better, but I think the fixed fee limit should always to be above the typical base fee multiplied by typical amount of hops, so that would mean 100% is not enough for very small amounts. (I don't know the numbers, but maybe it's like 5-10 sats total?)

But I don't know how to make a nice GUI for that logic.