Pull bitcoin tx

[oxf71]

Closes: #29

1. add load bitcoin config
2. add bitcoin indexer service pull bitcoin tx

Description

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For contributor use:

• [ ] Targeted PR against correct branch (see CONTRIBUTING.md)
• [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• [ ] Code follows the module structure standards.
• [ ] Wrote unit and integration tests
• [ ] Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• [ ] Added relevant godoc comments.
• [ ] Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• [ ] Re-reviewed Files changed in the Github PR explorer

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For admin use:

• [ ] Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• [ ] Reviewers assigned
• [ ] Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)