Hermes incompatible with newer Margo versions

[marcvef]

Linked to GekkoFS issue here: https://storage.bsc.es/gitlab/hpc/gekkofs/-/issues/255

Since there are several new Margo versions, it is not clear if below issues are the full list to make Hermes compatible with the latest Margo version v0.13. Margo version 0.9.9 is the last functioning version.

These issues have been reproduced both with Mercury 2.1.0 and 2.2.0 with similar behavior:

1. In Margo v0.9.10, GekkoFS daemons receive RPC requests and respond. However, the response never reaches the client. This commit causes the issue as it introduces a serialization mechanism to induce a header to each RPC. Margo v0.910 is mainly adding this change
2. Margo changed setting the default provider id which isn't set in the compatibility layer. This is fixed by marcvef@088710d . The corresponding Margo commit is causing this change is relevant for release v0.10.
3. (May very well be a side effect to 2) In Margo v0.13, if serialization mechanism is removed manually from the Margo code (for debugging purposes), daemons receive RPC requests but they the input structs are empty. I mention this for the sake of completeness, but I assume that this is because the serialization introduced in commit is integrated more into Margo. And therefore, removing serialization by this commit is not enough.

TODO in addition: A testing environment to easily test new Margo versions.