build!: Remove unused github action and sql file.

This automation has been making these PRs to update this file but no one
has been merging them and it doesn't look like the sql file is being
used by devstack.

BREAKING CHANGE: This removes the edxapp.sql file and a regularly
running github action.  If you are relying on that file, this commit
will break you.  My search didn't turn up anything that would be using
this file but I might have missed something.

.github/workflows/mysqldbdump.yml

@@ -1,23 +0,0 @@
-name: mysqldbdump
-on:
-  schedule:
-    - cron: '0 8 * * *'
-jobs:
-  mysqldbdump:
-    name: mysqldbdump
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout repo
-        uses: actions/checkout@v2
-      - name: Migrate
-        run: docker-compose -f ./.github/workflows/docker-compose.yml.mysqldbdump up -d
-      - name: Wait for migration to complete
-        uses: jakejarvis/wait-action@master
-        with:
-          time: '900s'
-      - name: Dump database
-        run: docker exec -i edx.devstack.mysql57 mysqldump -u'edxapp001' -p'password' --skip-dump-date edxapp > edxapp.sql
-      - name: Commit dump file to repo.
-        run: ./.github/workflows/mysqldbdump_pr.sh
-        env:
-          GH_ACCESS_TOKEN: ${{ secrets.EDX_DEPLOYMENT_GH_TOKEN }}

.github/workflows/mysqldbdump_pr.sh

@@ -1,39 +0,0 @@
-#! /usr/bin/env bash
-
-export GITHUB_USER='edx-deployment'
-export GITHUB_TOKEN=$GH_ACCESS_TOKEN
-export GITHUB_EMAIL='edx-deployment@edx.org'
-export REPO_NAME='edx-platform'
-export DB_NAME='edxapp'
-
-cd ..
-
-# install hub
-curl -L -o hub.tgz https://github.com/github/hub/releases/download/v2.14.2/hub-linux-amd64-2.14.2.tgz
-tar -zxvf hub.tgz
-
-cd "$REPO_NAME"
-
-if [[ -z $(git status -s) ]]; then
-    echo "No changes to commit."
-else
-    git config --global user.name "${GITHUB_USER}"
-    git config --global user.email "${GITHUB_EMAIL}"
-
-    obsolete_dump_prs=`../hub-linux*/bin/hub pr list -s open --format '%I:%H %n' | grep 'github-actions-mysqldbdump'`
-
-    if [[ ! -z $obsolete_dump_prs ]]; then
-      for pr in $obsolete_dump_prs; do
-        IFS=':' read pr_num branch <<< "$pr"
-        ../hub-linux*/bin/hub issue update ${pr_num} -s closed
-        ../hub-linux*/bin/hub push origin --delete ${branch}
-      done
-    fi
-
-    git checkout -b github-actions-mysqldbdump/$GITHUB_SHA
-    git add "${DB_NAME}".sql
-    git commit  -m "MySQLdbdump" --author "GitHub Actions MySQLdbdump automation <admin@edx.org>"
-    git push --set-upstream origin github-actions-mysqldbdump/$GITHUB_SHA
-    ../hub-linux*/bin/hub pull-request -m "${DB_NAME} MySQL database dump" -m "MySQL database dump" -l mysqldbdump
-
-fi