Add BPMs and RF devices to db

[nneveu]

We should try to address some of the needs in @williamColocho 's presentation here: 2026_07_22_lcls_liveDB.pdf

The desired getters are:

• def get_mapping_by_pvname(pvname: str):
• def get_mappings_by_bmad_element(bmad_ele_name: str):
• def get_mappings_by_device_type(device_type: str):
• def pv_to_bmad_value(pvname: str, epics_value: float):
• def get_klystron(sector: int, station: int):
• def get_klystrons_for_sector(sector: int):
• def get_element(element_name: str):
• def get_elements_by_keyword(keyword: str):
• def get_elements_by_area(area: str)

First step should be adding one of the following to device db generator/reader functions:

• BPMs (BPMS: pv base)
• KLYS (ACCL: or KLYS: pv base)
• SC Cavities (ACCL: pv base)