Add DynamicPPL integration tests

[penelopeysm]

This PR adds the Turing/DynamicPPL integration tests (from the test/turing folder in DynamicPPL) to this repository instead.

The main motivation behind this PR is to ensure that the tests added here are always run whenever a new version of Turing is released, thus making it impossible to release a version of Turing that contains a buggy version of DynamicPPL. See TuringLang/DynamicPPL.jl#703 for more thorough explanation.

Some implementation details:

• I made each test file its own module. This mimics the structure of the other tests in Turing.jl.
• I had to add AbstractPPL and BangBang as explicit test depedencies (previously they were transitive deps).
• Because the DynamicPPL integration tests run very quickly, it's probably OK for to run them under the 'everything else' bucket in the CI setup. Hence this PR makes no change to the CI.
• I fixed a couple of deprecation warnings (specifically link!(vi, sampler) -> link!!(vi, sampler, model); the same with invlink!; and AutoReverseDiff(false) -> AutoReverseDiff(; compile=false)).

Otherwise, this is a straight copy paste.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.41%. Comparing base (f4beee9) to head (9506316).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2393   +/-   ##
=======================================
  Coverage   86.41%   86.41%           
=======================================
  Files          22       22           
  Lines        1575     1575           
=======================================
  Hits         1361     1361           
  Misses        214      214           

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[coveralls]

Pull Request Test Coverage Report for Build 12054932691

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 122 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-7.8%) to 78.585%

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Files with Coverage Reduction	New Missed Lines	%
src/mcmc/hmc.jl	122	0.0%

Totals
Change from base Build 12053229696:	-7.8%
Covered Lines:	1233
Relevant Lines:	1569

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💛 - Coveralls