make openssl install less confusing, align openssl version

Summary:
X-link: https://github.com/facebookincubator/fizz/pull/152

X-link: https://github.com/facebookincubator/zstrong/pull/1073

On linux getdeps uses system openssl,  on macOS we mostly use the homebrew one on github CI. Both of these are openssl3.x,  however the fallback build from source version is still set as openssl1.1.  This can be confusing, giving the impression getdeps based builds need openssl1.1
* Update the openssl manifest source url to openssl-3.0.15,  this version picked to match the ubuntu 22.04 LTS system packages.

The other potentially confusing part was that the openssl source tarball was downloaded even when on on a platform like Linux where openssl is always taken from the system packages.
* Make the download configurable so that does nothing if satisfied from system packages, and no need to check the cache.

Reviewed By: ckwalsh

Differential Revision: D66495352

fbshipit-source-id: 4d24bb82bfabe44c7764b819de7f4a05f80daed1

build/fbcode_builder/getdeps.py

@@ -333,6 +333,12 @@ class FetchCmd(ProjectCmdBase):
 
         cache = cache_module.create_cache()
         for m in projects:
+            fetcher = loader.create_fetcher(m)
+            if isinstance(fetcher, SystemPackageFetcher):
+                # We are guaranteed that if the fetcher is set to
+                # SystemPackageFetcher then this item is completely
+                # satisfied by the appropriate system packages
+                continue
             cached_project = CachedProject(cache, loader, m)
             if cached_project.download():
                 continue
@@ -348,7 +354,6 @@ class FetchCmd(ProjectCmdBase):
                     continue
 
             # We need to fetch the sources
-            fetcher = loader.create_fetcher(m)
             fetcher.update()