[#451] Detach --regtest from local zcashd environment setup

[pacu]

This breaks the darksidewalletd tests on regtest since RegtestManager kicks in when the --regtest flag is specified.

In order to be able to point to a lightwalletd server in --darkside-very-insecure mode this has to be modified so callers can tell Zingolib that they won't be needing the RegtestManager at all.

closes #451

[codecov-commenter]

Codecov Report

Patch and project coverage have no change.

Comparison is base (587d485) 60.20% compared to head (874e58d) 60.20%.
Report is 2 commits behind head on dev.

❗ Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the GitHub App Integration for your organization. Read more.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev     #452   +/-   ##
=======================================
  Coverage   60.20%   60.20%           
=======================================
  Files          33       33           
  Lines        5375     5375           
=======================================
  Hits         3236     3236           
  Misses       2139     2139           

see 1 file with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[AloeareV]

I don't think this is necessary. The --regtest flag is a convenience for the specific scenario of zingo managing all of the binaries for you, but since the darkside tests don't want that, I think --chain regtest will do what you want here: connect to a regtest server but otherwise act like normal zingo.

[AloeareV]

@pacu let me know if you still need this, and I'll merge it

[pacu]

@AloeareV can you reopen this? I've updated it to the latest dev, don't merge because I need to test it again with the new code