Implement Fee Channels

[Varunram]

Currently, when an investors wants to invest $4000 in a project, only $3999.99 (or something along those lines) goes to the recipient. With scale in the number of investors, the amount received by recipients reduces proportionally. This fees can be paid for by the platform acting as a fee channel instead (and maybe we can charge investors for this).

More info: https://www.stellar.org/developers-blog/how-we-simplified-fees-on-the-stellar-network