* Changes to packaging code for new version (2.0.0) and add 'lal' to Debian and RPM packaging requirements.

* Fixed minor errors in packaging files.

Add lal to requirements

Fixed a comparison issue that produces syntax warnings in Python 3.8+.

Removed the dtd_uri_callback() function from dqsegdb code

Removed the dtd_uri_callback() from ligolw_segment_insert_dqsegdb and apicalls.py, since it's unused there, and it's implemented and used in glue/glue/segmentdb/query_engine.py.

* dqsegdb.apicalls: fix posting data to a URL

we need to submit data in bytes, not str

* dqsegdb.urifunctions: clean up payload encoding

* ligolw_segment_query_dqsegdb: remove the use-s6 option

we don't have s6 servers any more

* ligolw_segment_query_dqsegdb: remove commented-out code

Remove commented out code in some scripts

Remove unused code in ligolw_segments_from_cats_dqsegdb

Update client library manifest to exclude folders

Assorted changes leading toward dqsegdb 2.0.0

Fixed bug (typo) in dqsegdbCheckVersion and issue in same with flag versions as strings.  Addresses issues #48 and #83.

Details:
* client tools run on P3 by default now
* fixed some outdated email addresses and URLs
* lots of tweaks and fixes to documentation and comments
* added some new documentation
* created an issue for ligolw_segment_insert_dqsegdb '24k line issue' and added link in documentation
* fixed "ult_json=" typo in dqsegdb/apicalls.py

* debian: update packaging for python3

* spec: update packaging for python3

that are not required in a source distribution for the client

* dqsegdb.tests: add minimal pytest suite

mainly as a placeholder for some real tests

* ci: move to v2 of the codecov action

* ci: don't print coverage report from pytest

* add more tests for urifunctions

Rebase from upstream

This reverts commit 1302a0bc.

This commit prevents CI from passing for Python 2.7, and another user submitted a better (temporary) fix.

Migrate CI to github actions

with github actions/codecov badges

better doc