Go cleanup (Part 2)

[rolznz]

Followup of #101

Get what I can done from the following:

• move nip47 notifier into nip47 package
• move nip47 handler methods into nip47 package
• move wails code into wails package
• move service code into own package
• move tests out of main package
• split service package
• move main files into separate commands rather than using build tags - move to new issue
• Review how LSP and backup services are accessed by API - move these back into the API - not important for now
• Improve DB queries - join apps and permissions together - move to new issue Improve database performance #68
• Remove duplication publishing error responses in handlers not important for now
• Reduce duplication in multi_payment vs single payment methods not important for now
• Simplify Wails request router - not important for now
• Replace session auth with JWT auth, remove CSRF - move to new issue

Observations

• moved NIP-47 code out but everything is still very tightly coupled to the "service" package.
• lack of separation between running service (lnclient + relay + nip47) vs non-running service (only http/wails handlers)
• some things should use context but do not (for example a context for the duration of a lnclient running)
• service now has a lot of "Getters" which seem not good
• many tests are missing