rlm_totp: Backport changes from v3.2.x

[jpereira]

• Backport recent changes in rlm_totp from v3.2.x
• Move the TOTP functionality to libfreeradius-totp.a
• Add scripts/totp/totp-gen.py script to generate real token
• Add a new test against rlm_totp.

e.g:

$ make test.totp
TOTP-TEST INPUT=now_token_6digits.txt TOKEN=085509 TOTP_GEN_ARGV="-d 6 -D sha1"
TOTP-TEST INPUT=now_token_8digits.txt TOKEN=43085509 TOTP_GEN_ARGV="-d 8 -D sha1"
$

[alandekok]

I've pulled most of this over, except for a few pieces:

• I didn't revert the call_env stuff. That is likely not too hard
• the TOTP dictionary needs to be moved, but I ran into other issues with the dictionaries
• the last commit for tests needs the rlm_totp without the call_env stuff, so that's been left.

But the module builds and seems to work, so that's a step forward.