Prepare for GIS4WRF 0.14.7 release

[x] Create a milestone for the version to release if not done already.
[x] Check that all issues and PRs targeting the new release have been addded to the milestone.
[x] Check that the documentation repository is up to date.
[x] Check that the README file is up-to-date.
[x] Add and reference issues and PRs mentioned in the milestone to CHANGELOG.txt.
[x] Bump the version in the metadata.txt file.
[x] Check that all issues and PRs for the version number to release have been closed.
[x] Create the zip package.
[x] Test the zip package locally.
[x] Upload the zip package to the QGIS Python Plugins Repository.
[x] Confirm that the package has been approved on the QGIS Python Plugins Repository.
[x] Create a new release.
[x] Close the issue named Prepare for GIS4WRF <VERSION_NUMBER> release.

After release, the Ubuntu install instructions can be simplified to just "download/install QGIS using official instructions".

GIS4WRF / gis4wrf