api: refactor + new endpoint for ETC payout

[thelostone-mc]

Description

• remove sync/etc
• create new endpoint for bounty_fulfilment
• added fields to BountyFulfillment [ token_name, payout_tx_id, payout_status,
  payout_amount ]
• replaced etc sync checks to use BountyFulfillment as opposed to Bounty

[codecov]

Codecov Report

Merging #6094 into new-bounty-detail will decrease coverage by 6.55%.
The diff coverage is 13.58%.

@@                  Coverage Diff                  @@
##           new-bounty-detail    #6094      +/-   ##
=====================================================
- Coverage              28.89%   22.33%   -6.56%     
=====================================================
  Files                    273      263      -10     
  Lines                  24292    24260      -32     
  Branches                3564     3568       +4     
=====================================================
- Hits                    7018     5419    -1599     
- Misses                 16991    18805    +1814     
+ Partials                 283       36     -247

Impacted Files	Coverage Δ
app/app/urls.py	90.56% <ø> (ø)	⬆️
.../dashboard/management/commands/sync_etc_payouts.py	0% <0%> (ø)	⬆️
app/dashboard/models.py	35.63% <100%> (-18.96%)	⬇️
app/dashboard/utils.py	15.55% <18.75%> (-24.23%)	⬇️
app/dashboard/views.py	9.26% <5.35%> (-2.54%)	⬇️
app/app/context.py	0% <0%> (-68.54%)	⬇️
app/marketing/management/commands/sync_keywords.py	29.16% <0%> (-66.67%)	⬇️
app/marketing/management/commands/expiration.py	33.33% <0%> (-57.15%)	⬇️
app/avatar/templatetags/avatar_tags.py	0% <0%> (-54.55%)	⬇️
app/economy/utils.py	30.3% <0%> (-54.55%)	⬇️
... and 48 more

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