Extract signature_trie.py from verify_overlaps.py

Makes the efficient pattern matching of hidden API flags that is used
by verify_overlaps.py available for use in other scripts.

As part of the move this cleans up the python to use consistent quotes,
and fix pylint issues.

Bug: 202154151
Test: m out/soong/hiddenapi/hiddenapi-flags.csv
      atest --host signature_trie_test verify_overlaps_test
      pyformat -s 4 --force_quote_type double -i scripts/hiddenapi/signature_trie*
      /usr/bin/pylint --rcfile $ANDROID_BUILD_TOP/tools/repohooks/tools/pylintrc scripts/hiddenapi/signature_trie*
Change-Id: I758ca70bb5b7e6806f14b72fd04f821a069f188f

Change-Id: I73fdb7e02127a8c0171a285221d9e6024310953d