major usability fixes

[tomholub]

These are issues that frustrate me frequently.

• missing contact suggestions when composing email, searching contacts re-enable search contacts/recipietns on google once oauth permissions approved #283
• encryption of attachments slow and progress unclear Improve visual progress when sending message with attachments #695
• oauth grant friction during setup better handling of missing google grants - user guidance #531
• drafts not supported save drafts during compose or reply #514
• (waiting for Google verification of scope) few contacts found contact search finds very few contacts compared to gmail #743
• (in progress) missing conversation view in inbox support conversation view in inbox #608
• (waiting to merge) decryption of messages with attachments is slow, progress unclear allow opening messages of unlimited size + add download progress #783

later:

• have to repeatedly enter pass phrase, should instead use faceid [discuss] UX - Unlock with face id #456

[tomholub]

@fcvakintos please don't unpin issues I've pinned

[tomholub]

closing, #657 is last remaining issue