gnucash-docs: update to 4.8.

 4.8    - 28 September 2021
        o Remove outdated files.
        o Remove autotools.
 4.7    - 26 September 2021
        o Bug 798226 - minor mistakes in Tutorial and Concepts guide 2
        o Bug 798226 - postprocessing: xmlformat
        o Bug 798236 - Remove comment about swapped A/P & A/R terminology
        o Replace COPYING file from GPL 3 to GPL 2.
        o Substantial editing of the C documentation to make the meanings more
          understandable to translators.
        o Apply dtd-locale to help/de/Help_para-assist-intro.xml.
        o Add ENTITY(s) prefix guisubmenu, guimenuitem, and guilabel as gsm,
          gmi, and gl, respectively.
        o Move untranslated entity messages from gnc-docbookx.dtd to each
          locale file.
        o Make DTD ENTITY(s) translatable. See docbook/README.
          Bug 798273 - Consider a entity import system like in docbook-xsl
        o Guide:C:Currency: update images Part 1
        o Fix license file to use actual file instead of softlink.
        o Unify words and account names. Fix minor typos and tags. Add commas
          to the numbers. Add some tags. Fix according to the review comments.
        o Add license file to git tracking
          It is an autogenerated file from autotools but it was ignored by our
          current git config. A previous commit chose to install the file, but
          that's difficult if it's missing.
        o Install license files COPYING and COPYING-DOCS
        o Help/de: Crop Export screenshots
        o Drop travis-ci in favour of github worflows
        o Remove obsolete appendix B about FAQ from guide.
        o Remove obsolete appendix C about VAT from guide.
        o Guide/C: Note on fieldnames in CSV import
        o Mark Guide's import chapter as outdated
        o Minor improvements in C and de Help Tips on alphavantage


(wiz)