custom sqlite

[marcprux]

• Fixed some linker errors caused by WAL absence on Linux.
• Import Foundation for CGFloat on non-Darwin platforms
• Removed the #if !os(Linux) compiler directive in the Decimal extension, as it compiles fine under swift 6
• Removed #if !os(Linux) in NSString.swift, NSData.swift and Date.swift.
• Fixed fromDatabaseValue build under non-Darwin platforms
• Fixed databaseValue build for non-Darwin platforms.
• Fixed UUID fromDatabaseValue for non-Darwin platforms
• Fixed import in CGFloatTests.swift to work under non-Darwin platforms.
• Ignore FailureTestCase.swift entirely on non-Darwin platforms for now.
• Ignore ValueObservationRecorderTests.swift on non-Darwin platforms.
• Fixed the unit tests in DatabasePoolConcurrencyTests.
• Fixed the tests in DatabaseQueueTests.swift
• Fixed DatabaseSnapshotTests on non-darwin platforms
• Integrated upstream changes.
• It should be canImport(Darwin) not os(Darwin)
• Use #if !canImport(Combine) per test case (as done by @marcprux) and throw an XCTSkip for these test cases. This gives a better impression how many tests are skipped on Linux/non-Darwin platforms.
• NSError bridging is not available, or doesn't work the same on non-Darwin platforms. Skip testNSErrorBridging on these platforms.
• vscode config
• Fix Swiftlint warnings
• Remove obsolete TODOs
• Fix typos in usage examples
• SQLCipher adjustments to support forks which want to enable SQLCipher using traits/swiftSettings
• Fix typo in usage examples
• Adds Foundation import to Database+SQLCipher
• Removes GRDBSQLCipher import from SQLCipher conditional import in Database.swift to allow SQLCipher forkers versatility for defining pass-throughs to GRDB required sqlite variadic functions.
• Use the same logic for importing SQLCipher as in other files
• Do not define CipherLogLevel as a frozen enum
• Enhance documentation formatting
• Make links appear as links in DocC
• Support more SQLCipher log destinations
• Rename CipherXxx APIs to SQLCipherXxx when possible
• Prepare support for SPM+SQLCipher
• Document how to enable SQLCipher with SPM
• Minor typo in doc comments
• Add custom SQLite build and multi-platform CI