Add PyTorch Version of VAE, AE, SO_GAAL based on the DL base detector && Fix some bugs in DL base detector.

[RaymondY]

All Submissions Basics:

• [x] Have you followed the guidelines in our Contributing document?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• [x] Have you checked all Issues to tie the PR to a specific one?

All Submissions Cores:

• [x] Have you added an explanation of what your changes do and why you'd like us to include them?
• [x] Have you written new tests for your core changes, as applicable?
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• [x] Does your submission have appropriate code coverage? The cutoff threshold is 95% by Coversall.

[coveralls]

Pull Request Test Coverage Report for Build 9375439553

Details

• 507 of 521 (97.31%) changed or added relevant lines in 9 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 94.047%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pyod/test/test_vae.py	35	36	97.22%
pyod/test/test_so_gaal_new.py	75	77	97.4%
pyod/models/so_gaal_new.py	78	82	95.12%
pyod/models/base_dl.py	115	122	94.26%
<!--	Total:	507	521	97.31%	-->

Totals
Change from base Build 9328641231:	0.1%
Covered Lines:	9306
Relevant Lines:	9895

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💛 - Coveralls