feat: automatically detect client that is connected

[olavloite]

Automatically detects the client that is creating a connection to
PGAdapter based on the data that PGAdapter receives in the
StartupMessage. Not all clients can be uniquely identified this way, and
clients could easily pretend to be a client they are not, but this
feature is only used to automatically apply query replacements based on
the client that is connecting.

Fixes b/235348017

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (postgresql-dialect@30607f0). Click here to learn what that means.
The diff coverage is n/a.

@@                  Coverage Diff                  @@
##             postgresql-dialect     #169   +/-   ##
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  Coverage                      ?   78.61%           
  Complexity                    ?      989           
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  Files                         ?       89           
  Lines                         ?     3446           
  Branches                      ?      387           
=====================================================
  Hits                          ?     2709           
  Misses                        ?      583           
  Partials                      ?      154           

Flag	Coverage Δ
all_tests	78.61% <0.00%> (?)

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