Split out HTTP + Handlers

[thomshutt]

We're going to deprecate the giant PR in #30 and try to split it into a series of more manageable / reviewable ones.

This one creates a more manageable base in terms of package structure by only doing CLI stuff in the cmd package and moving HTTP layer functions into api. It also splits out handlers/handlers.go into different files based on functionality - e.g handlers/upload.go. It also moves the Mist client into the clients package.

[codecov]

Codecov Report

Merging #36 (e66b57f) into main (f8d600f) will decrease coverage by 0.29766%.
The diff coverage is 29.95595%.

@@                 Coverage Diff                 @@
##                main         #36         +/-   ##
===================================================
- Coverage   44.72441%   44.42675%   -0.29767%     
===================================================
  Files              8          12          +4     
  Lines            635         628          -7     
===================================================
- Hits             284         279          -5     
+ Misses           314         312          -2     
  Partials          37          37                 

Impacted Files	Coverage Δ
clients/mist_client.go	50.48544% <ø> (ø)
clients/mist_client_mock.go	0.00000% <ø> (ø)
handlers/handlers.go	100.00000% <ø> (+70.50000%)	⬆️
handlers/triggers.go	0.00000% <0.00000%> (ø)
middleware/logging.go	0.00000% <0.00000%> (ø)
handlers/transcode.go	44.44444% <44.44444%> (ø)
handlers/upload.go	47.76119% <47.76119%> (ø)
api/http.go	57.14286% <57.14286%> (ø)
handlers/ok.go	100.00000% <100.00000%> (ø)

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Impacted Files	Coverage Δ
clients/mist_client.go	50.48544% <ø> (ø)
clients/mist_client_mock.go	0.00000% <ø> (ø)
handlers/handlers.go	100.00000% <ø> (+70.50000%)	⬆️
handlers/triggers.go	0.00000% <0.00000%> (ø)
middleware/logging.go	0.00000% <0.00000%> (ø)
handlers/transcode.go	44.44444% <44.44444%> (ø)
handlers/upload.go	47.76119% <47.76119%> (ø)
api/http.go	57.14286% <57.14286%> (ø)
handlers/ok.go	100.00000% <100.00000%> (ø)

[emranemran]

LGTM - didn't find any issues with the logic but we can address after everything is merged and tested.