Truncate large issues to improve memory usage and log processing speed

[ecamacho]

• Adds a new flag truncateLargeIssues to instruct the parser to truncate the issues (either Warnings, Errors or Notes) of an individual task with more than a 100 issues. We bump into this issue when turning on Swift LTO that produced a task with around 40k duplicated warnings that blew up the memory used by XCMetrics. This flag is useful for cases like that in which the log do not produce any insightful data.
• Bumps XCLogParser to the version that supports that flag
• Removed some redundant code introduced in https://github.com/spotify/XCMetrics/pull/64
• Makes the new parameter Tag introduced in https://github.com/spotify/XCMetrics/pull/64 an Optional to provide backwards compatibility with old versions of the XCMetricsClient that were not sending that parameter, making the Backend to fail.

[ecamacho]

Sources/XCMetricsClient/Log Management/LogParser.swift was removed since it was not used. This was a leftover of when we moved the internal version to be open source