Reorganise and modernise the py-sqlalchemy ports.

• Introduce new ports for the sqlalchemy 0.9 and 1.0 release branches.
• Deprecate the ports for the 0.6 and 0.7 release branches, as these have been declared EoL and are no longer supported by upstream.
• Update to the latest available version in each branch.

In detail:

Port                 Version Maintainer
----------------------------------------------
py-sqlalchemy06      0.6.9   nivit@FreeBSD.org (Deprecate 2016-08-20) [1]
py-sqlalchemy07      0.7.10  nivit@FreeBSD.org (renamed py-sqlalchemy, Deprecate 2016-08-20) [1]
py-sqlalchemy08      0.8.7   nivit@FreeBSD.org (renamed py-sqlalchemy-devel) [1]
py-sqlalchemy09      0.9.10  m.tsatsenko@gmail.com (new, repocopy from py-sqlalchemy-devel) [2]
py-sqlalchemy10      1.0.13  m.tsatsenko@gmail.com (new, repocopy from py-sqlalchemy-devel) [2]

• Use options-helpers and option dependent make targets.
• Use autoplist for documents as well as python code
• Add all the docments to the packages: previously an arbitrary subset was added in a way that excluded CSS, images and other HTML assets.
• Use TEST_DEPENDS and add a TEST_TARGET instead of having a 'TEST' option.
• Use py-pytest for 0.9.x and later, rather than py-nose.
• Add CONFLICTS_INSTALL between all of the py-sqlalchemyXY ports.

PR: 191442
Submitted by: robak
Reviewed by: robak
Reviewed by: pi
Approved by: nivit (maintainer timeout, ~300days) [1]
Approved by: m.tsatsenko@gmail.com (maintainer) [2]
Sponsored by: https://reviews.freebsd.org/D908