build: detect new erlang version format correctly

- OTP 17.0 uses a different numbering system for releases and patches, but not semver.org
- the major version number will be bumped for the first time in 4 years
docs: update supported Erlang/OTP and SpiderMonkey versions

- matches what the code can support after last Mochiweb update
- update .travis.yml file to match 17.0 release
- update docs
Merge branch 'refs/heads/2200-feature-support-erlang-17.0'

- closes COUCHDB-2200

* refs/heads/2200-feature-support-erlang-17.0:
  docs: update supported Erlang/OTP and SpiderMonkey versions
  build: detect new erlang version format correctly
Fix comparison warning on ./configure