support sslcertsand other ssl based options on ConnOptions

[kolharsam]

Currently, on Hasura Cloud, we also support the connection of Postgres databases that require client-side SSL authentication. I wasn't sure if the connOptions

pg-client-hs/src/Database/PG/Query/Connection.hs

Line 71 in f46db20

, connOptions :: !(Maybe String)

within the record type ConnOptions would be enough or we would need to handle it separately.

[kolharsam]

Saving a reference to @jkachmar's comment here which is related to this issue: https://github.com/hasura/graphql-engine-mono/pull/1690#discussion_r661892351

[jkachmar]

Copying over the relevant context for pg-client-hs from the parent comment mentioned above.

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Currently, the code paths involved in graphql-engine all assume that Postgres connection info is only ever expressed and handled as a URI. pg-client-hs uses ConnDetails to express that it can handle either a URI or a record of connection parameters which can be used to construct a connection string (cf. the libpq reference docs for details).

I think it would be much nicer if we could extend pg-client-hs roughly as follows:

• add all of the connection parameters specified in the libpq documentation to ConnOptions
• have a function that can convert between a Postgres URI and a ConnOptions-based connection string losslessly
  • this might involve adding more fields to ConnOptions or it might just involve constructing an intermediate type that can hold all of the query parameters that ConnOptions is incapable of expressing