Feat: Vlang veb scenarios

[brmassa]

1. Vlang has only one representative server that is, in fact, a C library with a wrapper. Veb is the "official" Vlang web server. I've designed MySQL and PostgreSQL variants. Fell free to comment and analyze it.

2. Another addition is the direct usage of V's picoev to make a bare bone web server. picoev is used internally by Veb, but does not have the ORM or other features like middleware configuration.

3. Another change is the removal of pico.v bash startup script that spawns several pico.v programs. Since each one of them will receive part of the traffic, it seems like cheating. Note that are other server that use the same trick, but this PR only focus on the Vlang ones