move mcp-server-shared here as standalone(?) extension

[maxandersen]

in quarkus-mcp-servers I added a 'shared' module which does a few small but nice things:

0. sets up uber-jar packaging
1. provide a configsource based on the command line arguments (anything with -Dkey=value or -- gets set as a property)
2. handles that --sse activates SSE instead of default stdio; especially useful for devmode.
3. --debug activates logging
4. Option to set your own @QuarkusMain and reuse the code.

as is today it is with the above it ispossible to do:

quarkus create app -x io.quarkiverse.mcp.servers:mcp-server-shared:1.0.0.CR3 mcpapp and you have an app (no code starter)

I would suggest we add/move this shared module to quarkus-mcp-server + add a base codestart example so something like:

quarkus create app -x mcp-server-shared myapp would be sufficient.

But shared probably is not a good name. Maybe app? so it would be ``quarkus create app -x mcp-server-app myapp` ?

wdyt?

[maxandersen]

just realizing the isn't actually an extension but just a normal dependency; so can't do it in its current form.