Partially automate release - tagging and documentation generation [DI-669]

[JackPGreen]

Partially automates the steps listed in the C++ Client Release Process documentation.

Specifically, steps:

• Git tagging
• Doxygen

By scripting and chaining the steps, the (manual) release work is reduced and consistency is improved. Tagging logic based on approach in hazelcast-docker.

Where possible, I've tried to replicate how it currently works. It's likely there's future scope to improve (e.g. should the documentation updates really raise a PR?).

Of note - the instructions call for an "annotated tag" (tag -a). While this seems more sensible, it's not how we make tags elsewhere (most notably - in the release pipeline), so for consistency I've changed to lightweight tags.

Testing (in my fork):

• example execution
• tag created
• documentation PR raised

Post-merge actions:

• update docs

Partially addresses: DI-669

[nishaatr]

@JackPGreen
thanks for doing this
while we are at it lets automate Create branch at some point to make things little more easier. (I am sure you have considered this!)

[JackPGreen]

@JackPGreen thanks for doing this while we are at it lets automate Create branch at some point to make things little more easier. (I am sure you have considered this!)

🧙
#1366