PYCBC-1747: Add binding generation tools package

Modification
============
* Added tools/ package that includes binding autogen tooling
* Update .pre-commit config
* Update MANIFEST.in to exclude tools
* Set `couchbase::core::logger::level` enum to not go through
  autogen so Python side can appropriately map log levels

Change-Id: If3416e1d3d2b0c8f419b062ce1eee1427f13f784
Reviewed-on: https://review.couchbase.org/c/couchbase-python-client/+/240944
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: Dimitris Christodoulou <dimitris.christodoulou@couchbase.com>

Author: thejcfactor

.pre-commit-config.yaml

@@ -70,6 +70,7 @@ repos:
               txcouchbase/tests/|
               couchbase/tests/|
               tests/|
+              tools/|
               simple_acouchbase.py|
               simple_couchbase.py|
               simple_txcouchbase.py|

MANIFEST.in

@@ -74,3 +74,4 @@ include deps/couchbase-cxx-client/third_party/expected/COPYING
 graft deps/couchbase-cxx-client/third_party/expected/include
 global-exclude *.py[cod] *.DS_Store
 exclude .git .gitignore .gitmodules gocaves* *.jar .clang* .cmake* .pre* .flake* MANIFEST.in
+prune tools