change time datatypes to builtin int128

[mcb5637]

changes date/time 128 bit integer from boost to builtin __int128, to make calculations a lot faster.

while the builtin has a smaller range than boost, both are bigger than what the int64_t year allows. therefore the usable range of date/time types stays the same.

also fixes some possible (but very unlikely in regular use) overflow errors in date/time calculations (to trigger them, you need to use very big numbers, at least several orders of magnitude bigger than the end of the universe).

[sonarqubecloud]

Quality Gate failed

Failed conditions
0.0% Coverage on New Code (required ≥ 80%)
6.9% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud

[liss-h]

Could you add a little more context to the PR description? Like a summary of the changes and what the implications are (limits and such)