Remove openstack-doc-tools

openstack-doc-test has been removed from openstack-doc-tools in release
1.0.0. Remove it's usage from this project.

Also, remove doc-test.conf file, it was used by openstack-doc-tools.

Remove checkniceness and checksyntax targets, they are unused and not
needed. Merge doc8 check into pep8 and doc environments (note that
OpenStack CI does not use doc environment, so add it to pep8 as well) as
is custom for lint like jobs. Fix requirements to follow best practices.

Add doc8 to test-requirements to document its usage properly, add sphinx
there as well.

Change-Id: I97b9df8272c4f425ec516dfb84c29d2263c316f8

doc-test.conf

@@ -1,2 +0,0 @@
-[DEFAULT]
-repo_name = solar

test-requirements.txt

@@ -6,6 +6,8 @@ pytest-mock
 tox
 pytest-subunit
 os-testr
+doc8  # Apache-2.0
+sphinx
 
 ## for computable inputs
 # temporary disabled

tox.ini

@@ -5,43 +5,28 @@ envlist = pep8,py27
 
 [testenv]
 usedevelop = True
+deps = -r{toxinidir}/test-requirements.txt
 install_command = pip install -U {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
 passenv = SOLAR_DB
 
 [testenv:py27]
-deps = -r{toxinidir}/test-requirements.txt
 commands = ostestr
 
 [testenv:pep8]
 basepython=python2
-deps = hacking==0.10.2
 usedevelop = False
 commands =
     flake8 {posargs:solar}
-
+    doc8 doc
-[testenv:checkniceness]
-deps = openstack-doc-tools>=0.30
-       doc8
-commands =
-  openstack-doc-test --check-niceness
-  doc8 doc
-
-[testenv:checksyntax]
-deps = openstack-doc-tools>=0.30
-commands =
-  openstack-doc-test --check-syntax
 
 [testenv:docs]
 basepython=python2
-deps = sphinx
-       {[testenv:checkniceness]deps}
 whitelist_externals = /bin/rm
 commands =
   /bin/rm -rf doc/build
   python setup.py build_sphinx
-  {[testenv:checkniceness]commands}
+  doc8 doc
-  {[testenv:checksyntax]commands}
 
 [doc8]
 # Settings for doc8:
@@ -57,8 +42,6 @@ max-line-length = 80
 ignore = D000
 
 [testenv:venv]
-deps = -r{toxinidir}/requirements.txt
-       sphinx
 commands = {posargs:}
 
 [testenv:cover]