CI: Rename cmake.yml to serenity.yml

Just calling it "cmake" doesn't really describe what it is for, and a
future commit will add a lagom.yml. So let's call this serenity.yml to
make it clear that it tests SerenityOS itself.

This also renames the workflow, and updates some matrix orderings, to be
easier to distinguish between this job and the upcoming lagom.yml,

.github/workflows/serenity.yml

@@ -1,4 +1,4 @@
-name: Build, lint, and test
+name: SerenityOS
 
 on: [push, pull_request]
 
@@ -11,32 +11,30 @@ env:
   TOOLCHAIN_CCACHE_DIR: ${{ github.workspace }}/Toolchain/.ccache
 
 concurrency:
-  group: ${{ github.head_ref || format('{0}-{1}', github.ref, github.run_number) }}
+  group: ${{ github.workflow }}-${{ github.head_ref || format('{0}-{1}', github.ref, github.run_number) }}
   cancel-in-progress: true
 
 jobs:
-  build_and_test_serenity:
+  CI:
     runs-on: ${{ matrix.os }}
     if: github.repository == 'SerenityOS/serenity'
     strategy:
       fail-fast: false
       matrix:
-        debug-options: ['NORMAL_DEBUG']
+        toolchain: ['GNU', 'Clang']
         os: [ubuntu-22.04]
         arch: ['x86_64']
-        toolchain: ['GNU', 'Clang']
-        # If ccache is broken and you would like to bust the ccache cache on Github Actions, increment this:
-        ccache-mark: [0]
+        debug-options: ['NORMAL_DEBUG']
         include:
-          - debug-options: 'NORMAL_DEBUG'
+          - toolchain: 'GNU'
             os: ubuntu-22.04
             arch: 'aarch64'
-            toolchain: 'GNU'
+            debug-options: 'NORMAL_DEBUG'
 
-          - debug-options: 'ALL_DEBUG'
+          - toolchain: 'GNU'
             os: ubuntu-22.04
             arch: 'x86_64'
-            toolchain: 'GNU'
+            debug-options: 'ALL_DEBUG'
 
     steps:
       # Pull requests can trail behind `master` and can cause breakage if merging before running the CI checks on an updated branch.