* shiny-state.R (which_gui_inputs, which_metfrag_inputs,
unpack_app_state, unpack_app_state_metfrag, input2conf_metfrag,
input2conf, app_state2state): Updated. The inputs are defined
in a more structured manner and this resulted in having to update
the entire system of state creation fom GUI.

* shiny-ui-base.R : Updated. Temporary reorganisation while the
app.Rmd is being rebuilt.

* state.R(metfrag_param): New function. Creates MF parameter object.
(metfrag4conf): New function. Creates a conf entry.
(metfrag_conf): Updated.

* inst/rmd/app.Rmd: Under reconstruction.

* envopts (envopts): Update. Normalise MetFrag paths.

* resources (METFRAG_DATABASE_TYPE, METFRAG_REMOTE_DATABASE_TYPE,
METFRAG_LOCAL_DATABASE_TYPE): Updated. Rearranged for finer control.

* shiny-state (make_metfrag_panel): New function.

* shiny-ui-base (mf-database-type): New observer.
(cando_metfrag, metfrag_panel): New outputs.

* app (MetFrag): Update section header. Delete hardwired controls.
(metfrag_panel): New control which replaced the hardwired controls.

tests: Update with new functionality.

Everything under Measurement Properties refreshes correctly now. The
reason why it did not was the overuse of req functions.

app: Replaced qa_ms1[2] with qlt_ms1[2], changed how state is handled and fixed extract/prescreen stage in GUI.