Add option to encode UTF-8 BOM for MsBuild RSP file generation

Microsoft compilers and build tools expect some input files (such as the RSP file) to be encoded as UTF-8 BOM. Bamboo currently generates RSP files for the MsBuild task which are encoded UTF-8 no BOM.

Add UTF-8 BOM encoding option in the task configuration UI such that the user can select to generate a UTF-8 BOM RSP file which is more portable.

Workaround
Use a script task instead of MsBuild task. The script should: a) create the RSP file with the correct encoding, then b) call MSBuild and pass the resulting file as an argument.

Note: Make sure to set the correct code page for the shell from the script with the command:

 chcp 65001 

 before creating the RSP file.