Support libSQL adapter about knex

[rluvaton]

Custom dialects are supported

See this for example:

https://github.com/Tomas2D/knex-firebird-dialect

We should better document it though, a PR for that welcome

[TzviPM]

One thing I'm noticing so far is that there are documentation-esque comments in the code that are not doc comments. For example, in client.js:

// The base client provides the general structure
// for a dialect specific client object.

class Client extends EventEmitter {

Also, I'm wondering how it will work to build a dialect in pure typescript. There are type definitions for the external APIs, but not for the client code, AFAICT. Turns out there are type definitions for the Client API 👍🏼