utf8mb4 support

[bradymiller]

Initial testing is good. Still a bunch more testing to do:

1. On all 8 mysql/mariadb version (UPDATE: now just six :) ) DONE
2. Ensure backward compatible for upgraders DONE
3. Ensure actually working in all contexts (core, calendar, gacl, doctrine, portal, zend) DONE

[bradymiller]

Looks like mariadb 10.1 and mysql 5.6 have rather strict key size limits which are gonna require some effort to fix. Thinking best option is to drop support for mariadb 10.1 and mysql 5.6 since they are at end of life in 10/2020 and 2/2021 respectively anyways.

[bradymiller]

just a quick example of what utf8mb4 allows (emoticons in messages):

turns out utf8(which is utf8mb3) is limited since only uses 3 bytes, whereas pure utf8 should have 4 bytes (utf8mb4) and then allows many more characters (including some chinese characters missing from utf8mb3 and emoticons and bunch of other characters).

[tywrenn]

@bradymiller I enabled system emoticons through SCSS -- didn't realize that this was also a required step 😂

[bradymiller]

testing well and bringing this in (along with companion docker and demofarm changes). hopefully will not have to think about character sets and collations again for another 8 years :)