refactor(sqlite): getter/setter for maxConnections

[timvandam]

Summary of changes

Made SQLiteConnectionPool.maxConnections a protected property, and introduced getters and setters. There is similarly already a getter getActiveConnections(), and the new setter ensures that it is impossible to have more than 1 connection for in-memory databases

Relinquishment of Rights

Please mark following checkbox to confirm that you relinquish all rights of your changes:

• I waive and relinquish all rights regarding this changes (including code, text, and images) to Deepkit UG (limited), Germany. This changes (including code, text, and images) are under MIT license without name attribution, copyright notice, and permission notice requirement.

[codecov-commenter]

Codecov Report

Merging #393 (f5fb9d1) into master (2e72cff) will increase coverage by 1.11%.
The diff coverage is 80.00%.

@@            Coverage Diff             @@
##           master     #393      +/-   ##
==========================================
+ Coverage   77.09%   78.20%   +1.11%     
==========================================
  Files         120      169      +49     
  Lines       14824    17746    +2922     
  Branches     4012     4635     +623     
==========================================
+ Hits        11428    13878    +2450     
- Misses       3396     3868     +472     

Impacted Files	Coverage Δ
packages/sqlite/src/sqlite-adapter.ts	94.18% <80.00%> (ø)
packages/mysql/src/mysql-schema-parser.ts	97.14% <0.00%> (ø)
packages/sqlite/src/sqlite-platform.ts	59.83% <0.00%> (ø)
packages/mongo/src/client/client.ts	84.31% <0.00%> (ø)
packages/sqlite/src/sqlite-serializer.ts	100.00% <0.00%> (ø)
packages/mongo/src/client/connection.ts	84.36% <0.00%> (ø)
packages/mongo/src/client/command/dropIndexes.ts	14.28% <0.00%> (ø)
packages/sqlite/src/sql-filter-builder.sqlite.ts	100.00% <0.00%> (ø)
packages/mongo/src/client/command/delete.ts	100.00% <0.00%> (ø)
packages/mysql/src/mysql-platform.ts	100.00% <0.00%> (ø)
... and 40 more

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more