= A new parameter for specify max length of email local part

A new parameter `--spi-user-profile-declarative-user-profile-max-email-local-part-length` is added to set max email local part length taking backwards compatibility
into consideration. The default value is 64. Example of usage:

```
kc.[sh|bat] start --spi-user-profile-declarative-user-profile-max-email-local-part-length=100 ...
```