vault kv version and mount names in publish config

[ajvb]

Adds support for publishing to vault using KV v1 and a different mount name (or multiple).

Also further expands the "destination rule config" unit tests.

Supporting kv v1 and a different mount name came back to me from user testing of sops publish.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (develop@e9b9f7a). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff             @@
##             develop     #513   +/-   ##
==========================================
  Coverage           ?   36.46%           
==========================================
  Files              ?       20           
  Lines              ?     2863           
  Branches           ?        0           
==========================================
  Hits               ?     1044           
  Misses             ?     1725           
  Partials           ?       94

Impacted Files	Coverage Δ
config/config.go	71.42% <100%> (ø)

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