Improve SQLite3 parser

[JSCU-CNI]

This PR fixes the following two issues in the SQLite3 parser:

1. Make column expression and string regexes lazy instead of greedy, which adds compatibility for column definitions such as CHARACTER(int) and VARCHAR(int) (https://www.sqlite.org/datatype3.html#affinity_name_examples)
2. Do not throw InvalidPageNumber if the database header does not contain a page_count.

[Schamper]

Can you elaborate on the page_count change? Maybe why it's necessary or how you encountered it? Is it a corrupt database, or a valid database that can be created?

I've tried to reproduce with sqlite3 empty.db "VACUUM;" but that creates a database with page_count = 1 (and also has another issue with a 0 text_encoding which should also be fixed).

[JSCU-CNI]

Is it a corrupt database, or a valid database that can be created?

Certain old versions of SQLite3 do not set or update the header correctly. Bottom line is that other sqlite3 libraries do not seem to care if the page_count is zero. Reading through the dissect implementation it seems that the page_count is not really used either when iterating over tables.

It seems silly to throw a read out of bounds exception if we do not know the bounds, so that is why we added the page_count > 0 check.

[Schamper]

Can you add a comment explaining as such? ;)