[deps/stdlib] put all version info in Versions.make

[inkydragon]

I agree that there doesn't need to be both Versions.make and libname.version. We could combine the two (probably by just putting everything into Versions.make).

Originally posted by @staticfloat in #40430 (comment)

ref: #40430

• rm all *.version files, and put all version info in Versions.make
• fix 2 version mismatch: libblastrampoline and OpenBLAS
• add a comment for LibSSH2, why LIBSSH2_VER !== LIBSSH2_BRANCH

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Maybe we can backport this pr to other versions.

[DilumAluthge]

For stdlib, we actually want to keep each of the external stdlibs in their own file. See for example #41370 (comment). So this PR undoes the work we did in #42474.

#40430 was about deps, not stdlib. Can you remove the external stdlib changes from this PR?

[inkydragon]

Can you remove the external stdlib changes from this PR?

There is one small problem. Because the installation of stdlib calls the function stdlib-external, which in turn calls git-external. So we can't just have stdlib use a separate .version file.

Perhaps we could reuse the deprecated arguments of the git-external function, and add a new argument use_all_in_one_version_file so that we can distinguish between deps and stdlib.

[vtjnash]

We don't want to do this for deps either, since it means we can't determine as accurately when they need to be updated, and it increases the chances that backporting something ends up in a merge conflict. But we could probably move the BB versions into the .version files, to keep all of the ways of specifying it in one place.

[inkydragon]

replace by: #45720