Ethereum-Stellar bridge fees need to be adjusted

[sabrinasadik]

While network token transfer fees have been under $1 for the past two years, users are being charged 2000 TFT (equivalent to $12 USD).

Let's keep that up to market-standards.

See issue raised by the community: https://git.ourworld.tf/tfgrid_internal/circle_support/issues/37

[LeeSmet]

This requires a restart of the bridge and validators and therefore requires #282 to be done first for safety reasons (in case the persistency file gets nuked)

[shng4you]

@LeeSmet I just wanted to follow up on this issue. Thanks