misc lint/style improvements

[nomirosa]

we should write our own linter

• figure out how to check for unused links in RTD and build test for it
• add test to docs to check for trailing whitespace
• clarify the situation with line-wrapping in docs
• figure out how to properly handle images and standardize this everywhere (_static folders)
• go through and clean up paragraph formatting in all docs
• decide on the use of "consult" or "see" (e.g., https://github.com/docker-library/docs)
• fix up all historic instances of "fix" vs "fixed" in the changelog (and other related imperative mood changes)
• replace "table_ident" in docs with "my_table"
• go through all docs and replace references to "documents" (Lucene jargon)
• replace all :doc: statements with :ref: statements
• standardize docs reference string nomenclature
• (possibly) rewrap docs to match line width of GitHub diff comments so no ugly wrapping
• go through all repos, including docker-docs, and update "the project documentation" in the readme to drop the "the" from the hyperlink for consistency
• standardise header level of "Limitations" section at end of some docs

all lint checks should be documented in the style guide

[nomirosa]

needs splitting up