Create a main branch and use it for the FSR experiments

[sisuresh]

This branch will be used for the feature flag experiment mentioned at https://github.com/stellar/pod-fsr/issues/12#issuecomment-3942336873. Also delete curr/next or rename them to something like curr-do-not-use and next-do-not-use so they aren't used accidentally.

[leighmcculloch]

This reads like we will keep curr/next branches around. Can we remove them as part of this so there is just main? Even though it is an experiment still, I don't think we want folks accidentally making changes to curr/next, and if we need to move back, we can recreate the old branches.

[sisuresh]

This reads like we will keep curr/next branches around. Can we remove them as part of this so there is just main? Even though it is an experiment still, I don't think we want folks accidentally making changes to curr/next, and if we need to move back, we can recreate the old branches.

I updated the description to either delete or rename the branches.

[sisuresh]

We will keep curr and next around, but they should be generated from main. Mentioned here - https://github.com/stellar/pod-fsr/pull/19.