fix(relinker): Fixed replacement by searching by lower-case filenames

[kostua16]

Situation

• We have plugin called "MySuperPlugin.esp"
• We have script called "MySuperScript.pex" that contains code 'game.GetFormFromFile(1, "mySuperPlugin.esp")'
  OR
  We have script called "MySuperScript.pex" that contains code 'String EspFile = "mySuperPlugin.esp"'

Without ZMerge

• Game loads such plugins and scripts without issues, cause Windows doesn't differentiate "MySuperPlugin.esp" and "mySuperPlugin.esp".
• Expected = Actual

With ZMerge

• We have ZMerge that contains "MySuperPlugin.esp" and a result plugin called "MySuperMerge.esp"
• Relinker tries to re-link "MySuperScript.pex" but skips 'game.GetFormFromFile(1, "mySuperPlugin.esp")' cause there is no exact match.
• Relinker tries to re-link "MySuperScript.pex" but skips 'String EspFile = "mySuperPlugin.esp"' cause there is no exact match.
• Expected != Actual

Proposed solution

To do a lower-cased search that this pull request implements.
[X] Expected = Actual

Small note

The function that does lower-cased search moved to the "collectionUtils" helper to be re-used in case of future changes, but it's can be moved directly to "relinkedService" to reduce changes.