issues: 275164558

SQLite databases that use FTS include a number of automatically generated tables, e.g.:

https://sf-trees-search.now.sh/sf-trees-search-a899b92

Of these, only the Street_Tree_List table is actually relevant to the user.

We can detect which tables are FTS tables by first finding the virtual tables:

sqlite> .headers on
sqlite> select * from sqlite_master where rootpage = 0;
type|name|tbl_name|rootpage|sql
table|Search|Search|0|CREATE VIRTUAL TABLE "Street_Tree_List_fts" USING FTS4 ("qAddress", "qCaretaker", "qSpecies")

Then parsing the above to figure out which ones are USING FTS? - then assume that any table which starts with that Street_Tree_List_fts prefix was created to support search:

sqlite> select * from sqlite_master where type='table' and tbl_name like 'Street_Tree_List_fts%';
type|name|tbl_name|rootpage|sql
table|Search_content|Search_content|10355|CREATE TABLE 'Street_Tree_List_fts_content'(docid INTEGER PRIMARY KEY, 'c0qAddress', 'c1qCaretaker', 'c2qSpecies')
table|Search_segments|Search_segments|10356|CREATE TABLE 'Street_Tree_List_fts_segments'(blockid INTEGER PRIMARY KEY, block BLOB)
table|Search_segdir|Search_segdir|10357|CREATE TABLE 'Street_Tree_List_fts_segdir'(level INTEGER,idx INTEGER,start_block INTEGER,leaves_end_block INTEGER,end_block INTEGER,root BLOB,PRIMARY KEY(level, idx))
table|Search_docsize|Search_docsize|10359|CREATE TABLE 'Street_Tree_List_fts_docsize'(docid INTEGER PRIMARY KEY, size BLOB)
table|Search_stat|Search_stat|10360|CREATE TABLE 'Street_Tree_List_fts_stat'(id INTEGER PRIMARY KEY, value BLOB)

We won't hide these completely - instead, we'll default the database index view to not showing them with a message that says "5 hidden tables" and support ?_hidden=1 to display them.