[tpm2] tpm2-tools next release version 5.0

[tpm2] tpm2-tools next release version 5.0

[Roberts, William C]

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Hello,

As you likely already know, we follow semver.org versioning guidelines. For tpm2-tools next release from master, we are labelling it 5.0. I want to make
sure that everyone understands the changes around this. Unlike major version bumps 1, 2,3 and 4 command line options are staying the same in a
backwards compatible fashion (hooray). But there are some small changes coming, that I will highlight in the Changelog:
  - https://github.com/tpm2-software/tpm2-tools/blob/master/doc/CHANGELOG.md

The big takeaways are that the default algorithm for hashing is SHA256. Before, the man pages claimed SHA1, but this wasn't the case. The tools, hopefully
are all on SHA256 now as the default. Selecting SHA1 for the default wasn't optimal, as TPM2's whole purpose was algorithm agility to move away from SHA1.
Additionally the documentation did not match the code. SHA256 seems like a good choice, as all TPM's support it. The best bet, is to **always** specify the
hash algorithm, so you will never be surprised. If you do that, you wont have any backwards compat issues between 4.X and 5.X.

The other change is the busybox style commandlet. This will help reduce overall size and make some environments more convenient. To maintain
Backwards compat, make install provides symlinks to the new commandlet tpm2 from the old tool names. So something like tpm2_getrandom will be
symlinked to tpm2, and the commandlet will use argv[0] to figure it out. Thus, if you make install, or use a distro package, nothing should change. If you
run from a local build without installing, you can make install and set DESTDIR and just update your PATH entry if you need backwards compat.

I urge folks to start running master occasionally and let me know if something breaks between versions that isn't hightlighted in the CHANGELOG as
this could be a bug. I'd like to stomp these out sooner than later.

Thanks,
Bill