Input tips for web client

[astromark]

It would be nice to have useful tips on the web client for some of the inputs for example:
Obs freq: list equivalent wavelengths and ALMA bands
Bandwidth: suggested bandwidth for continuum observations
H2O profile percentile: relate to PWV
This info could appear when hovering the mouse of an input or require a click on a question mark next to that input.

[astromark]

For the suggested bandwidths for continuum observations, we now have the following from the SZ team (Di Mascolo et al., in prep.) who have looked into the optimum values (note that I need to go through #102 before these will give accurate answers). I plan to add this information in the documentation. I may also add it to the web page, but just as text for now as I don't have time for anything more complicated.

band	nu_start	nu_end	nu_mid	nu_width
[-]	[GHz]	[GHz]	[GHz]	[GHz]
-----	----------	----------	----------	----------
2	30	54	42	24
3	66	117	91.5	51
4	120	182	151	62
5	183	252	217.5	69
6	252	325	288.5	73
7	325	375	350	50
8	384	422	403	38
9	595	713	654	118
10	786	905	845.5	119