style(app): change default exports to named exports

[iansolano]

Change default exports to named exports in app and app-shell

overview

I'm trying to fix these linter warning in chunks to make merging and reviewing easier. This is the first bit, more to come. 😅

I will use this as the base branch and merge all the corresponding PRs into this branch

changelog

review requests

[mcous]

Bug due to inconsistent naming of the export from app-shell/src/log.js uncaught by flow due to low flow coverage in app-shell.

I think I'm also gonna ask to avoid arbitrary switching function declarations to anonymous arrow functions while we don't have consensus

[codecov]

Codecov Report

Merging #4822 into edge will increase coverage by 0.27%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##             edge   #4822      +/-   ##
=========================================
+ Coverage   57.92%   58.2%   +0.27%     
=========================================
  Files         956     960       +4     
  Lines       26237   26822     +585     
=========================================
+ Hits        15199   15611     +412     
- Misses      11038   11211     +173

Impacted Files	Coverage Δ
app-shell/src/ui.js	0% <ø> (ø)	⬆️
app-shell/src/buildroot/release-files.js	0% <ø> (ø)	⬆️
app/src/shell/epic.js	100% <ø> (ø)	⬆️
app/src/analytics/selectors.js	14.28% <ø> (ø)	⬆️
app-shell/src/update.js	100% <ø> (ø)	⬆️
app-shell/src/buildroot/index.js	0% <ø> (ø)	⬆️
app/src/util.js	100% <ø> (ø)	⬆️
app/src/analytics/hash.js	14.28% <ø> (ø)	⬆️
app/src/logger.js	0% <ø> (ø)	⬆️
app/src/analytics/mixpanel.js	13.04% <ø> (ø)	⬆️
... and 37 more

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[mcous]

🎂

Smoke tested dev and prod builds on my mac and everything looks good