Add config page

@charlie.hoy here is a candidate implementation of #5 (closed). Example of the results with configuration can be found at

• https://geo2.arcca.cf.ac.uk/~c1548640/LVC/projects/athena-warp-theory-2/issues/77-venv-for-pesummary/home.html
• https://geo2.arcca.cf.ac.uk/~c1548640/LVC/projects/athena-warp-theory-2/issues/77-venv-for-pesummary/html/IMRPhenomPv2_config.html
• https://geo2.arcca.cf.ac.uk/~c1548640/LVC/projects/athena-warp-theory-2/issues/77-venv-for-pesummary/html/IMRPhenomP_config.html