feat(litecoin): add litecoin support

[mrfelton]

Description:

Misc fixes and adjustments to get things working with litecoin nodes.

• ensure wallet info saves correctly
• support litecoin currency conversions
• remove bitcoin specific language
• patch bolt11 to support litecoin
• link to chain specific block explorers

Motivation and Context:

Support litecoin

How Has This Been Tested?

Manually - connect to a remote litecoin node and use the wallet

Types of changes:

Adjustments

Checklist:

• My code follows the code style of this project.
• I have reviewed and updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes where needed.
• All new and existing tests passed.
• My commits have been squashed into a concise set of changes.

[coblee]

Awesome! @losh11 will be able to review and test this soon.

[losh11]

tACK - however we'd prefer if the photons denomination is replaced by lites (ł). In Litecoin Core and various other wallets, by default we've also been using lites for a while now, and it would be preferred if Zap had consistency with these other wallets.

1 Litecoin (Ł) = 1,000 lites (ł)
Code otherwise looks perfect! 👍

[JimmyMow]

Tested ACK 3e826f2

@losh11 would you mind creating an issue for the lites request? I feel it is a bit out of scope for this PR as we first want some stable LTC functionality in place. Will follow up with a separate PR for the lites request