Move IdentityContext tables to the default schema

[VMelnalksnis]

Turns out Microsoft.Data.Sqlite does not support schemas, even though it's possible to get functionality equivalent to schemas by using ATTACH DATABASE

[codecov]

Codecov Report

Merging #791 (2ecad3e) into master (5c344e8) will increase coverage by 0.96%.
The diff coverage is 87.75%.

@@            Coverage Diff             @@
##           master     #791      +/-   ##
==========================================
+ Coverage   74.14%   75.11%   +0.96%     
==========================================
  Files         337      341       +4     
  Lines        9589    10198     +609     
==========================================
+ Hits         7110     7660     +550     
- Misses       2479     2538      +59     

Impacted Files	Coverage Δ
...grations/PostgreSQLIdentityContextModelSnapshot.cs	0.00% <0.00%> (ø)
...e/Migrations/SqliteIdentityContextModelSnapshot.cs	0.00% <0.00%> (ø)
...a.Sqlite/Migrations/20230504074721_RemoveSchema.cs	48.33% <48.33%> (ø)
...stgreSQL/Migrations/20230504074751_RemoveSchema.cs	53.73% <53.73%> (ø)
...Migrations/20230504074751_RemoveSchema.Designer.cs	100.00% <100.00%> (ø)
...shade.Data.PostgreSQL/PostgreSQLIdentityContext.cs	100.00% <100.00%> (ø)
...Migrations/20230504074721_RemoveSchema.Designer.cs	100.00% <100.00%> (ø)
...ce/Gnomeshade.Data.Sqlite/SqliteIdentityContext.cs	100.00% <100.00%> (ø)
source/Gnomeshade.Data/Identity/IdentityContext.cs	100.00% <100.00%> (ø)