Improve CI workflows in master, and branching model refactor (#371)

* Refs #21222. Making Ccache optional

Signed-off-by: Ricardo González Moreno <ricardo@richiware.dev>

* Refs #21226: Improve CI workflows in master and apply Fast DDS branching model

Signed-off-by: JesusPoderoso <jesuspoderoso@eprosima.com>

* Refs #21226: Add RELEASE_SUPPORT.md file

Signed-off-by: JesusPoderoso <jesuspoderoso@eprosima.com>

* Refs #21226: Add suggested changes from previous / similar PRs

Signed-off-by: JesusPoderoso <jesuspoderoso@eprosima.com>

* Refs #21226: Apply rev suggestion

Signed-off-by: JesusPoderoso <jesuspoderoso@eprosima.com>

* Refs #21226: Move 2.6.x related jobs to weekly CI

Signed-off-by: JesusPoderoso <jesuspoderoso@eprosima.com>

---------

Signed-off-by: Ricardo González Moreno <ricardo@richiware.dev>
Signed-off-by: JesusPoderoso <jesuspoderoso@eprosima.com>
Co-authored-by: Ricardo González Moreno <ricardo@richiware.dev>

.github/workflows/config/test.repos

@@ -0,0 +1,5 @@
+repositories:
+    googletest-distribution:
+        type: git
+        url: https://github.com/google/googletest.git
+        version: release-1.11.0

.github/workflows/nightly-ubuntu-ci.yml

@@ -0,0 +1,91 @@
+name: Fast DDS Gen Ubuntu CI (nightly)
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 1 * * *'
+
+jobs:
+  nightly-ubuntu-ci-master:
+    strategy:
+      fail-fast: false
+      matrix:
+        java-version:
+          - 'openjdk-11-jdk'
+          - 'openjdk-19-jdk'
+    uses: eProsima/Fast-DDS-Gen/.github/workflows/reusable-ubuntu-ci.yml@master
+    with:
+      os-version: 'ubuntu-22.04'
+      java-version: ${{ matrix.java-version }}
+      label: 'nightly-ubuntu-ci-master'
+      fastdds-gen-branch: 'master'
+      fastdds-branch: 'master'
+      fastcdr-branch: 'master'
+      fastdds-python-branch: 'main'
+      discovery-server-branch: 'master'
+      run-build: true
+      run-tests: true
+      use-ccache: false
+
+  nightly-ubuntu-ci-3_3_x:
+    strategy:
+      fail-fast: false
+      matrix:
+        java-version:
+          - 'openjdk-11-jdk'
+          - 'openjdk-19-jdk'
+        fastcdr-branch:
+          - '1.1.x'
+          - '2.x'
+    uses: eProsima/Fast-DDS-Gen/.github/workflows/reusable-ubuntu-ci.yml@3.3.x
+    with:
+      os-version: 'ubuntu-22.04'
+      java-version: ${{ matrix.java-version }}
+      label: 'nightly-ubuntu-ci-3.3.x'
+      fastdds-gen-branch: '3.3.x'
+      fastdds-branch: '2.14.x'
+      fastcdr-branch: ${{ matrix.fastcdr-branch }}
+      fastdds-python-branch: '1.4.x'
+      discovery-server-branch: 'v1.2.2'
+      run-build: true
+      run-tests: true
+      use-ccache: false
+
+  nightly-ubuntu-ci-3_2_x:
+    strategy:
+      fail-fast: false
+      matrix:
+        java-version:
+          - 'openjdk-11-jdk'
+          - 'openjdk-19-jdk'
+        fastcdr-branch:
+          - '1.1.x'
+          - '2.x'
+    uses: eProsima/Fast-DDS-Gen/.github/workflows/reusable-ubuntu-ci.yml@3.2.x
+    with:
+      os-version: 'ubuntu-22.04'
+      java-version: ${{ matrix.java-version }}
+      label: 'nightly-ubuntu-ci-3.2.x'
+      fastdds-gen-branch: '3.2.x'
+      fastdds-branch: '2.13.x'
+      fastcdr-branch: ${{ matrix.fastcdr-branch }}
+      fastdds-python-branch: '1.4.x'
+      discovery-server-branch: 'v1.2.2'
+      run-build: true
+      run-tests: true
+      use-ccache: false
+
+  nightly-ubuntu-ci-2_5_x:
+    uses: eProsima/Fast-DDS-Gen/.github/workflows/reusable-ubuntu-ci.yml@2.5.x
+    with:
+      os-version: 'ubuntu-22.04'
+      java-version: 'openjdk-11-jdk'
+      label: 'nightly-ubuntu-ci-2.5.x'
+      fastdds-gen-branch: '2.5.x'
+      fastdds-branch: '2.10.x'
+      fastcdr-branch: '1.0.x'
+      fastdds-python-branch: '1.2.x'
+      discovery-server-branch: 'v1.2.1'
+      run-build: true
+      run-tests: true
+      use-ccache: false