Make Example Great Again

[arcbtc]

resurrecting the Example extension, so we can add guides and examples for extension developers

[codecov-commenter]

Codecov Report

Merging #1321 (e7c479f) into main (7cfbb92) will increase coverage by 0.05%.
The diff coverage is 62.96%.

@@            Coverage Diff             @@
##             main    #1321      +/-   ##
==========================================
+ Coverage   48.30%   48.35%   +0.05%     
==========================================
  Files         278      282       +4     
  Lines       16295    16348      +53     
==========================================
+ Hits         7871     7905      +34     
- Misses       8424     8443      +19     

Impacted Files	Coverage Δ
lnbits/extensions/example/tasks.py	50.00% <50.00%> (ø)
lnbits/extensions/example/views_api.py	75.00% <66.66%> (ø)
lnbits/extensions/example/__init__.py	82.35% <80.00%> (ø)
lnbits/extensions/boltcards/views_api.py	22.47% <0.00%> (-0.79%)	⬇️
lnbits/extensions/example/views.py	90.00% <0.00%> (ø)
lnbits/wallets/spark.py	16.42% <0.00%> (+0.13%)	⬆️

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[callebtc]

MEGA

[arcbtc]

this is actually mergable as is, but I will add some bits first