Move eval_map to mmrotate.evaluation.

[liuyanyi]

Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily get feedback. If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.

Motivation

Move eval_map to mmrotate.evaluation.
Part of #54

Modification

Code follow mmdet.core.evaluation.
Add a parameter use_07_metric for eval_map to switch voc07/voc12 mode.

BC-breaking (Optional)

Does the modification introduce changes that break the back-compatibility of the downstream repos?
If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

If this PR introduces a new feature, it is better to list some use cases here, and update the documentation.

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. The documentation has been modified accordingly, like docstring or example tutorials.

[codecov-commenter]

Codecov Report

Merging #73 (4b5535f) into dev (dd40984) will increase coverage by 0.07%.
The diff coverage is 10.59%.

@@            Coverage Diff             @@
##              dev      #73      +/-   ##
==========================================
+ Coverage   28.76%   28.83%   +0.07%     
==========================================
  Files         102      104       +2     
  Lines        6571     6578       +7     
  Branches      985      985              
==========================================
+ Hits         1890     1897       +7     
  Misses       4617     4617              
  Partials       64       64              

Flag	Coverage Δ
unittests	28.82% <10.59%> (+0.07%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmrotate/core/evaluation/eval_map.py	7.58% <7.58%> (ø)
mmrotate/datasets/dota.py	15.78% <66.66%> (+4.61%)	⬆️
mmrotate/core/__init__.py	100.00% <100.00%> (ø)
mmrotate/core/evaluation/__init__.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update dd40984...4b5535f. Read the comment docs.

[zytx121]

LGTM