v1.0.0 — first release

Bump VERSION to 1.0.0 and cut the first tagged release of vpp-maglev.

Also in this commit:

- maglevc: MAGLEV_SERVER env var as an alternative to the --server
  flag, matching the MAGLEV_CONFIG / MAGLEV_GRPC_ADDR convention on
  the other binaries. The flag takes precedence when both are set.
- Rename cmd/maglevd -> cmd/server and cmd/maglevc -> cmd/client so
  the source directory names are decoupled from binary names (the
  frontend and tester commands already followed this convention).
  Build outputs and the Debian packages are unchanged.

docs/maglevc.1

@@ -28,13 +28,14 @@ Type
 .B ?
 at any point to list completions without advancing the input.
 .SH OPTIONS
+Flags may also be supplied via an environment variable (shown in
+parentheses where applicable); the flag takes precedence.
 .TP
 .BI \-server " addr"
 Address of the
 .B maglevd
 gRPC server.
-(default:
-.IR localhost:9090 )
+.RI "(default: " localhost:9090 "; env: " MAGLEV_SERVER )
 .TP
 .BR \-color [=\fIbool\fR]
 Colorize static field labels in output using ANSI dark blue. The
@@ -45,6 +46,9 @@ or files stays free of escape codes. Pass
 or
 .B \-color=false
 explicitly to override the default for either mode.
+.TP
+.B \-version
+Print version, commit hash, and build date, then exit.
 .SH EXAMPLES
 Open the interactive shell (no command on the command line). Tab
 completes the current token; typing