Replace otapi3 workflows with legacy variants

No need for otapi3 branch workflows here

.github/workflows/ci-otapi3.yml

@@ -1,55 +0,0 @@
-name: CI(OTAPI3)
-
-on: [push]
-
-jobs:
-  test:
-    runs-on: windows-latest
-
-    steps:
-      - uses: actions/checkout@v2
-        with:
-          submodules: 'recursive'
-
-      - uses: actions/setup-dotnet@v1
-        with:
-          dotnet-version: '6.0.100'
-
-      - name: Run tests
-        run: dotnet test
-
-  build:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        arch: ["win-x64", "osx-x64", "linux-x64", "linux-arm64", "linux-arm"]
-
-    steps:
-      - uses: actions/checkout@v2
-        with:
-          submodules: 'recursive'
-
-      - uses: actions/setup-dotnet@v1
-        with:
-          dotnet-version: '6.0.100'
-
-      - name: Produce build
-        run: |
-            cd TShockLauncher
-            dotnet publish -r ${{ matrix.arch }} -f net6.0 -c Release -p:PublishSingleFile=true --self-contained false
-
-      - name: Chmod scripts
-        if: ${{ matrix.arch != 'win-x64' }}
-        run: |
-            chmod +x TShockLauncher/bin/Release/net6.0/${{ matrix.arch }}/publish/TShock.Server
-
-      # preserve file perms: https://github.com/actions/upload-artifact#maintaining-file-permissions-and-case-sensitive-files
-      - name: Archive artifact
-        run: |
-            cd TShockLauncher/bin/Release/net6.0/${{ matrix.arch }}/publish/
-            tar -cvf ../../../../../../TShock-Beta-${{ matrix.arch }}-Release.tar *
-
-      - uses: actions/upload-artifact@v2
-        with:
-          name: TShock-Beta-${{ matrix.arch }}-Release
-          path: TShock-Beta-${{ matrix.arch }}-Release.tar