chore: Remove crescent provider (backport #402)

[mergify]

Description

closes: #XXXX

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Author Checklist

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please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• added appropriate labels to the PR
• targeted the correct branch
• provided a link to the relevant issue or specification
• added a changelog entry to CHANGELOG.md
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• reviewed "Files changed" and left comments if necessary
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• manually tested (if applicable)

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This is an automatic backport of pull request #402 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 2216d80 has failed:

On branch mergify/bp/release/v0.1.x/pr-402
Your branch is up to date with 'origin/release/v0.1.x'.

You are currently cherry-picking commit 2216d80.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   config/currency_provider_tracker.go
	modified:   config/supported_assets.go
	modified:   oracle/oracle.go
	deleted:    oracle/provider/crescent.go
	modified:   oracle/provider/provider.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by them: oracle/provider/crescent_test.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally