feat: add API methods to get allocations and claims

[simlecode]

关联的Issues (Related Issues)

#5287
lotus pr：filecoin-project/lotus#9437

改动 (Proposed Changes)

附注 (Additional Info)

自查清单 (Checklist)

在你认为本 PR 满足被审阅的标准之前，需要确保 / Before you mark the PR ready for review, please make sure that:

• 符合Venus项目管理规范中关于PR的相关标准 / The PR follows the PR standards set out in the Venus project management guidelines
• 具有清晰明确的commit message / All commits have a clear commit message.
• 包含相关的的测试用例或者不需要新增测试用例 / This PR has tests for new functionality or change in behaviour or not need to add new tests.
• 包含相关的的指南以及文档或者不需要新增文档 / This PR has updated usage guidelines and documentation or not need
• 通过必要的检查项 / All checks are green

[codecov-commenter]

Codecov Report

Merging #5374 (6ecb0d6) into release/v1.8.0-pre-rc (71342c2) will decrease coverage by 0%.
The diff coverage is 0%.

Additional details and impacted files

@@                  Coverage Diff                   @@
##           release/v1.8.0-pre-rc   #5374    +/-   ##
======================================================
- Coverage                     24%     24%    -1%     
======================================================
  Files                        605     605            
  Lines                      67662   67785   +123     
======================================================
- Hits                       16836   16831     -5     
- Misses                     48650   48777   +127     
- Partials                    2176    2177     +1     

[hunjixin]

LGTM