Attempt to reduce the number of calls to execute and fetchone.

Profiling has shown that there are many calls to sqlite3.execute and
fetchone which takes a signicant amount of time. A simple way of
reducing these is to swap the 2-stage init of table row data into a
unified add.

Applying this to add_set and add_country yielded these results:

Before changes
```
281784    7.054    0.000    7.054    0.000 {method 'execute' of 'sqlite3.Cursor' objects}
127443    1.114    0.000    1.114    0.000 {method 'fetchone' of 'sqlite3.Cursor' objects}
```

After changes
```
281714    7.492    0.000    7.492    0.000 {method 'execute' of 'sqlite3.Cursor' objects}
127373    1.217    0.000    1.217    0.000 {method 'fetchone' of 'sqlite3.Cursor' objects}
```

Note: The total time of fetchone has actually increased. I am hoping
this was an abnormality on my machine and the actual reduction in the
number of calls will permantly reduce this total time.

jellyfin_kodi/objects/kodi/queries.py

@@ -44,14 +44,6 @@ create_movie = """
 SELECT      coalesce(max(idMovie), 0)
 FROM        movie
 """
-create_set = """
-SELECT      coalesce(max(idSet), 0)
-FROM        sets
-"""
-create_country = """
-SELECT      coalesce(max(country_id), 0)
-FROM        country
-"""
 create_musicvideo = """
 SELECT      coalesce(max(idMVideo), 0)
 FROM        musicvideo
@@ -319,12 +311,12 @@ add_unique_id_movie_obj = ["{Unique}", "{MovieId}", "movie", "{UniqueId}", "{Pro
 add_unique_id_tvshow_obj = ["{Unique}", "{ShowId}", "tvshow", "{UniqueId}", "{ProviderName}"]
 add_unique_id_episode_obj = ["{Unique}", "{EpisodeId}", "episode", "{UniqueId}", "{ProviderName}"]
 add_country = """
-INSERT INTO     country(country_id, name)
-VALUES          (?, ?)
+INSERT INTO     country(name)
+VALUES          (?)
 """
 add_set = """
-INSERT INTO     sets(idSet, strSet, strOverview)
-VALUES          (?, ?, ?)
+INSERT INTO     sets(strSet, strOverview)
+VALUES          (?, ?)
 """
 add_set_obj = ["{Title}", "{Overview}"]
 add_musicvideo = """