Create "Core" Table Once and Then Never Again

[alexdanilowicz]

We only need to create the SPLIT_TEXT_TABLE once and then never again. This should be a "Core" table that is created on initialize. This will greatly improve performance because then the WordCount and EmojiCount (and I imagine a word by day chart) tables can just read from this core table, which is created only once.

The core table could also already exclude stopWords, unicode characters, etc, so we don't have to run those WHERE clauses multiple times.

[alexdanilowicz]

As part of this, we should also have a REGEX on the core table to get rid of punctuation and contractions.

[alexdanilowicz]

Also, do we even need a top_friends_table core table? Could we just query directly every time? Querying directly might make filtering easier. Filters we probably want: is_from_me, group_message, person, date.

[alexdanilowicz]

As part of this ticket, I think I'll change it so that there is no concept of a Emojis, Word, or Friends table. Instead there are just core tables and we query off of those core tables every time.