feat(plugins): allow adding custom themes

[j-a-m-l]

Proposed changes

This PR includes a way to load and select new UI themes.

This PR depends on #1191 to deal with permissions

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING documentation
• Lint and unit tests pass locally with my changes

[codecov-io]

Codecov Report

Merging #1194 into next will decrease coverage by 0.4%.
The diff coverage is 3.07%.

@@            Coverage Diff             @@
##             next    #1194      +/-   ##
==========================================
- Coverage   39.29%   38.88%   -0.41%     
==========================================
  Files         224      224              
  Lines        5935     6000      +65     
  Branches     1184     1200      +16     
==========================================
+ Hits         2332     2333       +1     
- Misses       3405     3460      +55     
- Partials      198      207       +9

Impacted Files	Coverage Δ
...omponents/Wallet/WalletExchange/WalletExchange.vue	8.33% <ø> (ø)	⬆️
src/renderer/store/modules/session.js	34.48% <ø> (+0.29%)	⬆️
src/renderer/App.vue	0% <0%> (ø)	⬆️
...components/App/AppSidemenu/AppSidemenuSettings.vue	0% <0%> (ø)	⬆️
src/renderer/pages/Profile/ProfileNew.vue	7.77% <0%> (+0.8%)	⬆️
src/renderer/store/modules/plugin.js	0% <0%> (ø)	⬆️
src/renderer/pages/Profile/ProfileEdition.vue	8.54% <0%> (-0.23%)	⬇️
src/renderer/mixins/session.js	0% <0%> (ø)	⬆️
src/renderer/services/plugin-manager.js	2.19% <0%> (-0.2%)	⬇️
...rc/renderer/components/MarketChart/MarketChart.vue	28.57% <66.66%> (-2.2%)	⬇️
... and 5 more

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[alexbarnsley]

@j-a-m-l do you have an example plugin I can test this with?

[j-a-m-l]

@alexbarnsley https://github.com/j-a-m-l/ark-desktop-wallet-dark-contrast

[alexbarnsley]

I like this 👍

[luciorubeens]

Beautiful theme 🌮!

• It can overwrite the built-in themes (light/dark) without the user editing the profile;
• When the plugin is removed or disabled the wallet does not apply any default theme.

[j-a-m-l]

@luciorubeens I've made several changes.

About overwriting user styles, it can happen everywhere, as the security testing plugin demonstrated. We don't have a good solution for that. At most we could try to remove rules before/after injecting the CSS, but it wouldn't matter, since users could include them on HTML or using new tricks.

changed