Write bond information into H5MD trajectories

**Is your feature request related to a problem? Please describe.**
In the simulations using molecules, we could write into the H5MD file which atoms are considered to form bonds.

Then, we could check if this information is read correctly by software like MDANSE.

**Describe the solution you'd like**
If we define molecules in MDMC, the information about them should be retained in the output H5MD trajectory.

**Describe alternatives you've considered**
We can ignore it and find bonds/molecules manually using MDANSE.

**Additional context**
Is there some more detailed description of how to write the topology of the system into an H5MD file? So far I've seen this:
https://www.nongnu.org/h5md/h5md.html#connectivity-group